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                                                                   EXHIBIT 99.25


                     BOSTON PROPERTIES LIMITED PARTNERSHIP

                          CERTIFICATE OF DESIGNATIONS

              ESTABLISHING AND FIXING THE RIGHTS, LIMITATIONS AND

                  PREFERENCES OF A SERIES OF PREFERRED UNITS

     Reference is made to the Second Amended and Restated Agreement of Limited
Partnership (the "Partnership Agreement") of Boston Properties Limited
Partnership, a Delaware limited partnership (the "Partnership"), of which this
Certificate of Designations (this "Certificate") shall become a part.
Capitalized terms used herein and not defined herein have the meanings ascribed
thereto in the main part of the Partnership Agreement.  Section references are
(unless otherwise specified) references to sections in this Certificate.

     WHEREAS, Section 14.1.B(3) of the main part of the Partnership Agreement
permits the General Partner, without the consent of the Limited Partners, to
amend the Partnership Agreement for the purpose of setting forth and reflecting
in the Partnership Agreement the designations, rights, powers, duties, and
preferences of holders of any additional Partnership Interests issued pursuant
to Section 4.2.A of the main part of the Partnership Agreement; and

     WHEREAS, the General Partner desires by this Certificate to so amend the
Partnership Agreement as of this 12th day of November, 1998 (the "Closing
Date").

     NOW, THEREFORE, the General Partner has set forth in this Certificate the
following description of the preferences and other rights, voting powers,
restrictions, limitations as to distributions, qualifications and terms and
conditions of conversion and redemption of a class and series of Partnership
Interest to be represented by Partnership Units which shall be referred to as
"Series Three Preferred Units":

     (1) Designation and Number.  A series of Preferred Units, designated the
         ----------------------                                              
         "Series Three Preferred Units," is hereby established.

     (2) Definitions.  For purposes of this Certificate of Designations, the
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         following terms shall have the meanings indicated:

     "Cash Business Combination" means a Transaction in which the fair market
     value of the aggregate consideration into which the outstanding Common
     Units are or will be exchanged or converted, or which holders of such Units
     will be entitled to receive, consists of 40% or less voting common equity.
     In determining whether a Transaction is a Cash Business Combination, the
     following will apply: (a) if elections for the type of consideration may be
     made by the holders of Common Units, it will be assumed that all holders of
     Common Units elect or will elect consideration other than voting common
     equity, (b) the determination shall be made in good faith by the General
     Partner, based on the fair market values of the consideration to be issued
     in the Transaction as of the date the definitive merger or other agreement
     relating thereto is entered into, and (c) if
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     any of the consideration to be issued in the Transaction is a publicly
     traded security, the fair market value of that security shall be the
     Current Market Price of such security as of the date the definitive merger
     or other agreement relating thereto is entered into.

     "Closing Date" shall have the meaning set forth in the recitals above.

     "Conversion Price" shall mean the conversion price per Common Unit for
     which the Series Three Preferred Units are convertible, as such Conversion
     Price may be adjusted pursuant to Section 7 hereof.  The initial Conversion
     Price shall be an amount equal to $38.10 per REIT Share.

     "Conversion Date" shall have the meaning set forth in paragraph (d) of
     Section 7 hereof.

     "Conversion Period" shall have the meaning set forth in paragraph (a) of
     Section 7 hereof.

     "Conversion Right" shall have the meaning set forth in paragraph (a) of
     Section 7 hereof.

     "Current Market Price" of a REIT Share or of a publicly traded security of
     any other issuer for any day shall mean the last reported sales price,
     regular way, on such day, or, if no sale takes place on such day, the
     average of the reported closing bid and asked prices on such day, regular
     way, in either case as reported on the New York Stock Exchange ("NYSE") or,
     if such security is not listed or admitted for trading on the NYSE, on the
     principal national securities exchange on which such security is listed or
     admitted for trading or, if not listed or admitted for trading on any
     national securities exchange, on the Nasdaq National Market or, if such
     security is not quoted on such Nasdaq National Market, the average of the
     closing bid and asked prices on such day in the over-the-counter market as
     reported by Nasdaq or, if bid and asked prices for such security on such
     day shall not have been reported through Nasdaq, the average of the bid and
     asked prices on such day as furnished by any NYSE member firm regularly
     making a market in such security selected for such purpose by the Chief
     Executive Officer of the Partnership or the General Partner.  "Current
     Market Price" of a Common Unit as of any day means the Current Market Price
     of a REIT Share multiplied by the Conversion Factor, as such term is
     defined in the main part of the Partnership Agreement.

     "Distribution Payment Date" shall mean the fifteenth day of February, May,
     August and November, in each year, commencing on November 16, 1998;
     provided, however, that if any Distribution Payment Date falls on any day
     other than a Business Day, the distribution payment due on such
     Distribution Payment Date shall be paid on the first Business Day
     immediately following such Distribution Payment Date.

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     "Distribution Periods" shall mean quarterly distribution periods from and
     after a Distribution Payment Date and to and excluding the next succeeding
     Distribution Payment Date (other than the initial Distribution Period,
     which shall commence on the day after the Closing Date and end on and
     exclude November 16, 1998).

     "Fair Market Value" shall mean the average of the daily Current Market
     Prices per Common Unit during the ten (10) consecutive Trading Days
     selected by the Partnership commencing not more than 20 Trading Days
     before, and ending not later than, the earlier of the day in question and
     the day before the "ex" date with respect to the issuance or distribution
     requiring such computation. The term "`ex' date," when used with respect to
     any issuance or distribution, means the first day on which REIT Shares
     trade regular way, without the right to receive such issuance or
     distribution, on the exchange or in the market, as the case may be, used to
     determine that day's Current Market Price.

     "Forced Conversion" has the meaning set forth in Section 7(b) hereof.

     "Forced Conversion Amount" shall mean the number of Series Three Preferred
     Units which the General Partner may require to be converted as provided in
     paragraph 7(b);

     "Forced Conversion Option" shall have the meaning set forth in paragraph
     (b) of Section 7 hereof.

     "Issue Date" shall mean, with respect to a Series Three Preferred Unit, the
     day after the Closing Date.

     "Junior Preferred Units" shall mean any class or series of Partnership
     Units the holders of which are entitled to the receipt of distributions or
     of amounts distributable upon liquidation, dissolution or winding up, as
     the case may be, junior in priority to the holders of the Series Three
     Preferred Units, but senior in priority to the holders of Common Units.

     "Junior Units" shall mean the Common Units and any other class or series of
     Partnership Units constituting junior units within the meaning set forth in
     paragraph (a) of Section 9 hereof.

     "Liquidation Preference" shall have the meaning set forth in paragraph (a)
     of Section 4 hereof.

     "Option Strike Date" shall have the meaning set forth in paragraph (a) of
     Section 5 hereof.

     "Parity Units" shall have the meaning set forth in paragraph (b) of 
     Section 9 hereof.

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     "Preferred Rate" shall mean, at any given time, the rate per annum as to
     which distributions accrue on each Series Three Preferred Unit, based on
     the Liquidation Preference, for purposes of determining the Stated
     Quarterly Distribution in effect at such time, as set forth in the
     following schedule:

     Time Period                               Preferred Rate
     -----------                               --------------
     November 12, 1998 to March 31, 1999            5.0%
     April 1, 1999 to December 31, 1999             5.5%
     January 1, 2000 to December 31, 2000           5.625%
     January 1, 2001 to December 31, 2001           6.0%
     January 1, 2002 to December 31, 2002           6.5%
     January 1, 2003 to May 12, 2009                7.0%
     May 13, 2009 and thereafter                    6.0%

     "Ratchet Distribution" shall mean for each Distribution Payment Date a
     distribution payable, if applicable, per Series Three Preferred Unit in
     respect of the Distribution Period ending on such Distribution Payment
     Date.  The Ratchet Distribution for each Distribution Period shall be equal
     to the distribution which would have been paid in respect of such Series
     Three Preferred Unit had (i) such Series Three Preferred Unit been
     converted into (x) a number of Common Units determined by dividing the
     Liquidation Preference by the Conversion Price in effect on such
     Distribution Payment Date and any (y) Other Securities (as defined below)
     issuable upon such conversion and (ii) there had been paid in respect of
     each such Common Unit and Other Securities (including any fractional
     portion thereof to the fourth decimal) a distribution (the "Regular
     Distribution") equal to the regular, quarterly cash distribution paid to
     holders of record of Common Units and Other Securities on that record date
     (the "Reference Record Date") which is closest to the end of the calendar
     quarter preceding such Distribution Payment Date.  For purposes of
     determining the Ratchet Distribution, in the event that a special cash
     distribution was paid to holders of Common Units and Other Securities on
     the Reference Record Date or at any time prior to the Reference Record Date
     and after the last record date for regular, quarterly cash distributions,
     then in such event the Ratchet Distribution shall include, in addition to
     the Regular Distribution paid in respect of the Reference Record Date, the
     amount of such special cash distribution paid in respect of each Common
     Unit or Other Security (for clarity, it is noted that the effect of this
     sentence is to assure that in calculating the Ratchet Distribution the
     holders of Series Three Preferred Units will benefit from any cash
     distributions paid in respect of Common Units and Other Securities even if
     such cash distributions might not be characterized as "regular, quarterly
     cash distributions").  In the event that a Series Three Preferred Unit is
     outstanding for only a portion of a Distribution Period, then the Ratchet
     Distribution with respect to such Series Three Preferred Unit and such
     Distribution Period shall be determined as provided in the preceding
     sentence but shall then be adjusted by multiplying such amount by a
     fraction, the numerator of which equals the number of days such Series
     Three Preferred Unit had been outstanding during such period and the
     denominator of which shall equal the total number of days during such
     Distribution Period.  As used herein, the term "Other 

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     Security" means any security in addition to Common Units (including
     Junior Preferred Units) which may be issuable to a holder of Series Three
     Preferred Units upon conversion of a Series Three Preferred Unit.

     "Redemption Notice" shall have the meaning set forth in paragraph (b) of
     Section 5 hereof.

     "Redemption Right" shall have the meaning set forth in paragraph (a) of
     Section 5 hereof.

     "Securities" shall have the meaning set forth in paragraph (g)(iii) of
     Section 7 hereof.

     "Source Agreements" shall mean that certain Master Transaction Agreement
     dated September 28, 1998 by and among the General Partner, the Partnership
     and, among others, the holders of the Series Three Preferred Units
     designated hereby, and each of the other agreements contemplated therein.

     "Stated Quarterly Distribution" shall mean for each Distribution Payment
     Date a distribution payable, if applicable, per each Series Three Preferred
     Unit in respect of the Distribution Period ending on such Distribution
     Payment Date.  The Stated Quarterly Distribution for each Distribution
     Period shall equal the sum of the following products for each day in such
     Distribution Period on which the Series Three Preferred Unit is
     outstanding: (i) the Preferred Rate in effect on such day divided by 365,
     multiplied by (ii) the Liquidation Preference.

     "Target Amount" shall mean that number of Series Three Preferred Units
     having a Liquidation Preference equal to one-sixth of the aggregate
     Liquidation Preference of the Series Three Preferred Units issued under the
     Source Agreements.

     "Trading Day" shall mean any day on which the securities in question are
     traded on the New York Stock Exchange ("NYSE"), or if such securities are
     not listed or admitted for trading on the NYSE, on the principal national
     securities exchange on which such securities are listed or admitted, or if
     not listed or admitted for trading on any national securities exchange, on
     the Nasdaq National Market, or if such securities are not quoted on such
     Nasdaq National Market, in the applicable securities market in which the
     securities are traded.

     "Transaction" shall have the meaning set forth in paragraph (h) of 
     Section 7 hereof.

     (3)  Distributions.
          ------------- 

          (a) The holders of Series Three Preferred Units shall be entitled to
              receive, in respect of each Distribution Payment Date, when, as
              and if authorized and declared by the General Partner out of
              assets legally available for

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              that purpose, cumulative preferential distributions payable in
              cash in an amount per Series Three Preferred Unit equal to the
              greater of (i) the Stated Quarterly Distribution for such
              Distribution Payment Date or (ii) the Ratchet Distribution for
              such Distribution Payment Date. Such distributions shall, with
              respect to each Series Three Preferred Unit, be cumulative from
              and including its Issue Date, whether or not in, or with respect
              to, any Distribution Period or Periods (i) such distributions are
              declared, (ii) the Partnership is contractually prohibited from
              paying such distributions or (iii) there shall be assets of the
              Partnership legally available for the payment of such
              distributions, and shall be payable quarterly, when, as and if
              authorized and declared by the General Partner, in arrears on
              Distribution Payment Dates, commencing on the first Distribution
              Payment Date after the Issue Date of such Series Three Preferred
              Units. Distributions are cumulative from the most recent
              Distribution Payment Date to which distributions have been paid,
              whether or not, or with respect to, in any Distribution Period or
              Periods (i) such distributions are declared, (ii) the Partnership
              is contractually prohibited from paying such distributions or
              (iii) there shall be assets legally available therefor. Each such
              distribution shall be payable in arrears to the holders of record
              of the Series Three Preferred Units, as they appear on the records
              of the Partnership at the close of business on such record dates,
              not more than 30 days preceding the applicable Distribution
              Payment Date (the "Distribution Payment Record Date") (or, in the
              case of a Distribution Payment Record Date that coincides with a
              record date for payment of distributions on Common Units, not more
              than 60 days preceding the applicable Distribution Payment Date),
              as shall be fixed by the General Partner; provided, however, that
              with respect to the first Distribution Period, the Distribution
              Payment Record Date for such period will be on or after the Issue
              Date. Accrued and unpaid distributions for any past Distribution
              Periods and any additional amounts as provided in subsection (f)
              may be authorized and declared and paid at any time, without
              reference to any regular Distribution Payment Date, to holders of
              record on such date, not exceeding 45 days preceding the payment
              date thereof (or, in the case of a record date that coincides with
              a record date for payment of distributions on Common Units, not
              more than 60 days preceding the applicable payment date thereof),
              as may be fixed by the General Partner.

          (b) The first Distribution Period with respect to the first Series
              Three Preferred Units issued shall be for the period from on and
              after the Closing Date to the first Distribution Payment Date of
              (and excluding) November 16, 1998.

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          (c) So long as any Series Three Preferred Units are outstanding, no
              distributions (whether in cash or in kind or upon liquidation of
              the Partnership), except as described in the immediately following
              sentence, shall be authorized and declared or paid on any series
              or class or classes of Parity Units for any period nor shall any
              Parity Units be redeemed, purchased or otherwise acquired for any
              consideration or any moneys to be paid to or made available for a
              sinking fund for the redemption of any Parity Units, directly or
              indirectly (except by conversion into or exchange for Parity Units
              or Junior Units), unless full cumulative distributions, including,
              if applicable, the further preferential distribution provided in
              subsection (f), have been or contemporaneously are authorized and
              declared and paid on the Series Three Preferred Units for all
              Distribution Periods terminating on or prior to the distribution
              payment date on (or date of purchase, redemption or other
              acquisition of) such class or series of Parity Units. When
              distributions are not paid in full upon the Series Three Preferred
              Units and any other class or classes of Parity Units, all
              distributions authorized upon the Series Three Preferred Units and
              any other class or classes of Parity Units shall be authorized and
              declared ratably in proportion to the respective amounts of
              distributions accumulated and unpaid on the Series Three Preferred
              Units and such Parity Units (which shall not include any accrual
              in respect of unpaid distributions for prior distribution periods
              if such Parity Units do not have a cumulative distribution).

          (d) So long as any Series Three Preferred Units are outstanding, no
              distributions (other than distributions paid solely in Junior
              Units, or options, warrants or rights to subscribe for or purchase
              Junior Units) shall be authorized and declared or paid or other
              distribution authorized and declared or made upon Junior Units for
              any period, nor shall any Junior Units be redeemed, purchased or
              otherwise acquired (other than a redemption, purchase or other
              acquisition of Common Units made for purposes of and in compliance
              with requirements of employee incentive or employee benefit plans
              of the Partnership or the General Partner or any of their
              subsidiaries), for any consideration (or any moneys to be paid to
              or made available for a sinking fund for the redemption of any
              Junior Units) by the Partnership, directly or indirectly (except
              by conversion into or exchange for Junior Units), unless in each
              case (i) the full cumulative distributions on all outstanding
              Series Three Preferred Units, including, if applicable, the
              further preferential distribution provided in subsection (f), and
              any other Parity Units of the Partnership shall have been paid for
              all past Distribution Periods with respect to the Series Three
              Preferred Units and all past distribution periods with respect to
              such Parity Units and (ii) sufficient funds shall have been paid
              for or irrevocably set aside and designated for payment of the

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              distribution due for the current Distribution Period with respect
              to the Series Three Preferred Units.

          (e) Without limiting the other provisions hereof, no distributions on
              Series Three Preferred Units (other than liquidating distributions
              made in accordance with Section 13.2 of the main part of the
              Partnership Agreement and Section 4 hereof) shall be paid by the
              Partnership at such time as the terms and provisions of any
              agreement of the Partnership or its affiliates or subsidiaries,
              relating to bona fide indebtedness for borrowed money, prohibits
              such declaration or payment or provides that such declaration or
              payment would constitute a breach thereof or a default thereunder,
              or if such declaration or payment shall be restricted or
              prohibited by law (and such failure to pay distributions on the
              Series Three Preferred Units shall prohibit other distributions by
              the Partnership as described in Sections 3(c) and (d)).

          (f) Notwithstanding the foregoing, distributions on the Series Three
              Preferred Units shall accrue whether or not the terms and
              provisions set forth in Section 3(e) hereof at any time prohibit
              the current payment of distributions, whether or not the
              Partnership has earnings, whether or not there are funds legally
              available for the payment of such distributions and whether or not
              such distributions are declared. Accrued but unpaid distributions
              on the Series Three Preferred Units will accumulate as of the
              Distribution Payment Date on which they first become payable and a
              further preferential distribution at the per annum rate then
              applicable for the period or periods specified in subsection (a)
              above shall accrue during the period of accumulation and be
              distributed in respect of such unpaid distributions until the
              amount thereof and the further preferential amount thereon shall
              have been distributed in full.

          (g) Upon liquidation, dissolution or winding up of the Partnership, no
              distributions shall be made to any series or class or classes of
              Junior Units until after payment shall have been made in full to
              the holders of the Series Three Preferred Units, as provided in
              Section 4(a).

          (h) Any distribution made on the Series Three Preferred Units shall
              first be credited against the further preferential distribution
              provided in subsection (f) above and then against the earliest
              accrued but unpaid distribution due with respect to such Series
              Three Preferred Units which remains payable. Other than
              liquidating distributions described in Section 4, the Series Three
              Preferred Units shall be entitled only to the distributions on the
              Series Three Preferred Units as described in this Section 3.

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     (4)  Liquidation Preference.
          ---------------------- 

          (a) In the event of any liquidation, dissolution or winding up of the
              Partnership, whether voluntary or involuntary, before any payment
              or distribution of the assets of the Partnership (whether capital
              or surplus) shall be made to the holders of Junior Units, the
              holders of the Series Three Preferred Units shall be entitled to
              receive Fifty Dollars ($50.00) per Series Three Preferred Unit
              (the "Liquidation Preference") or, if greater, the amount which
              each holder would receive in respect of the Common Units and Other
              Securities and property it would receive upon conversion of its
              Series Three Preferred Units if all Series Three Preferred Units
              were converted pursuant to Section 7 immediately prior to the
              distribution of liquidation proceeds under the Partnership
              Agreement, plus an amount equal to all distributions (whether or
              not earned or declared) accrued and unpaid thereon pursuant to
              Section 3 to the date of final distribution to such holder; but
              such holders of Series Three Preferred Units shall not be entitled
              to any further payment. If, upon any such liquidation, dissolution
              or winding up of the Partnership, the assets of the Partnership,
              or proceeds thereof, distributable among the holders of Series
              Three Preferred Units shall be insufficient to pay in full the
              preferential amount aforesaid and liquidating payments on any
              other Parity Units, then such assets, or the proceeds thereof,
              shall be distributed among the holders of such Series Three
              Preferred Units and any such other Parity Units ratably in
              accordance with the respective amounts that would be payable on
              such Series Three Preferred Units and any such other Parity Units
              if all amounts payable thereon were paid in full.

          (b) Upon any liquidation, dissolution or winding up of the
              Partnership, after payment shall have been made in full to the
              holders of the Series Three Preferred Units and Parity Units, as
              provided in this Section 4, any series or class or classes of
              Junior Units shall, subject to any respective terms and provisions
              applying thereto, be entitled to receive any and all assets
              remaining to be paid or distributed.

          (c) After payment of the full amount of the liquidating distributions
              to which they are entitled pursuant to Sections 4(a) and (b), the
              holders of Series Three Preferred Units will have no right or
              claim to any of the remaining assets of the Partnership.

          (d) The consolidation or merger of the Partnership with or into any
              other corporation, partnership, trust or entity or of any other
              corporation, partnership, trust or entity with or into the
              Partnership, or an exchange of Units or partnership interests, or
              the sale, lease or conveyance of all

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              or substantially all of the property or business of the
              Partnership (unless the net proceeds of any of the foregoing
              transactions shall be distributed to the holders of Units rather
              than reinvested), shall not be deemed to constitute a liquidation,
              dissolution or winding up of the Partnership.

     (5)  Redemption.
          ---------- 

          (a) Subject to adjustment as provided in this Section 5, on each of
              May 12, 2009; May 12, 2010; May 12, 2011; May 14, 2012; May 14,
              2013; and May 12, 2014 (each an "Option Strike Date") (i) each of
              the Series Three Preferred Unit holders, upon giving prior written
              notice as provided below, shall have the right (the "Redemption
              Right") to require that the Partnership redeem for cash, at a
              redemption price of $50 per Series Three Preferred Unit, Series
              Three Preferred Units held by such holder; provided that the
              maximum number of Series Three Preferred Units that may be
              required to be redeemed from all such holders is equal to the
              Target Amount; provided, further, that a holder may not exercise
              the Redemption Right for less than one thousand (1,000) Series
              Three Preferred Units or, if such holder holds less than one
              thousand Series Three Preferred Units, all of the Series Three
              Preferred Units held by such holder; and (ii) the General Partner,
              upon giving prior written notice as provided below, shall have the
              Redemption Right to require the redemption for cash, at a
              redemption price of $50 per Series Three Preferred Unit, of a
              number of Series Three Preferred Units equal to, but not in excess
              of, the Target Amount (in the aggregate from all holders);
              provided, however, that the General Partner may not require the
              redemption by the Partnership on any Option Strike Date of more
              than the lesser of (A) the Target Amount in respect of such Option
              Strike Date or (B) such number of Series Three Preferred Units as
              shall have an aggregate Liquidation Preference equal to the excess
              of (i) the aggregate Liquidation Preference of the sum of the
              Target Amounts for all prior Option Strike Dates and the currently
              applicable Option Strike Date over (ii) the aggregate Liquidation
              Preference of all Series Three Preferred Units previously
              converted (including Forced Conversions), noticed for conversion
              on such Option Strike Date, previously redeemed, and noticed for
              redemption on such Option Strike Date.

              The exercise of a Redemption Right on any Option Strike Date
              shall not be cumulative (i.e., the Target Amount with respect to
              any Option Strike Date is the maximum number of Series Three
              Preferred Units subject to mandatory redemption by either the
              Partnership or the holders of Series Three Preferred Units on each
              Option Strike Date); any Series Three Preferred Units that are not
              converted pursuant to Section 7 or redeemed

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              pursuant to this Section 5 on or before May 12, 2014 shall remain
              outstanding and shall have all of the rights and preferences set
              forth in this Certificate except that the provisions of this
              Section 5 shall not apply to any Series Three Preferred Units
              outstanding after such date.

          (b) In order to exercise its Redemption Right, a holder of Series
              Three Preferred Units shall deliver a notice (a "Redemption
              Notice," such term to also include the notice required to be
              delivered by the General Partner upon exercise of its Redemption
              Right) in the form attached hereto as Exhibit B to the Partnership
              (with a copy to the General Partner) not less than 40 nor more
              than 70 days prior to an Option Strike Date. If a holder of Series
              Three Preferred Units who has delivered a Redemption Notice
              pursuant to this Section 5 converts the Units tendered for
              redemption prior to the redemption date, the Redemption Notice
              shall be deemed revoked. The General Partner may exercise its
              Redemption Right by delivering in writing a Redemption Notice,
              containing the information provided in subsection (e), to each
              holder of record of Series Three Preferred Units, not less than 30
              nor more than 70 days prior to an Option Strike Date.

              If, pursuant to the exercise of a Redemption Right by holders of
              the Series Three Preferred Units, with such redemption to be
              effective on an Option Strike Date, holders tender for redemption
              a number of Series Three Preferred Units having an aggregate
              Liquidation Preference greater than the Target Amount, the
              Partnership may redeem all such Units tendered for redemption or a
              lesser number of Units, as the General Partner determines in its
              sole discretion, but not less than the Target Amount; provided,
              however, that if the Partnership does not redeem all Series Three
              Preferred Units so tendered for redemption, the Partnership shall
              redeem Units ratably from each tendering holder in proportion to
              the respective number of Units tendered. If the holders have
              tendered for redemption a number of Series Three Preferred Units
              less than the Target Amount and the General Partner delivers a
              Redemption Notice to redeem a number of Series Three Preferred
              Units greater than the number of Units tendered for redemption by
              the holders, the Partnership shall first redeem the Series Three
              Preferred Units of those holders exercising their Redemption Right
              pursuant to this Section 5 and shall then redeem, on a pro rata
              basis, Series Three Preferred Units from all holders who hold
              Units after giving effect to such redemption; provided, however,
              that in such case, (i) the General Partner shall deliver a
              separate notice at least 30 days prior to the Option Strike Date,
              containing the information provided in subsection (e), to all
              holders of the Series Three Preferred Units to be so redeemed
              indicating

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              the number of Units to be so redeemed, and (ii) the total number
              of Units to be redeemed (upon notice by the General Partner and
              the holders, collectively) shall not exceed the Target Amount.

              If the General Partner delivers a Redemption Notice to the
              holders of the Series Three Preferred Units, the holders shall
              have the right, subject to Section 7(a), to convert their Series
              Three Preferred Units into Common Units, pursuant to Section 7, on
              or before the Option Strike Date. To the extent that such Series
              Three Preferred Units are so converted, the right of the General
              Partner to require the redemption of Series Three Preferred Units
              shall be reduced by the aggregate Liquidation Preference of the
              Series Three Preferred Units so converted (and the reduction in
              the number of Series Three Preferred Units to be redeemed from
              each holder shall be allocated first to the holders who so elected
              to convert their Units and second pro rata among all other
              holders).

              Within two Business Days of a redemption of Series Three
              Preferred Units, the Partnership shall pay the redemption price by
              certified check to or on the order of those holders whose Series
              Three Preferred Units have been redeemed.

          (c) Immediately prior to any redemption of Series Three Preferred
              Units and as a condition to such redemption, the Partnership shall
              pay, in cash, all accumulated and unpaid distributions, including
              the further preferential distribution provided in Section 3(f),
              through the Option Strike Date in respect of all Series Three
              Preferred Units, including those Series Three Preferred Units to
              be redeemed. Unless full cumulative distributions on all Series
              Three Preferred Units have been paid, the Partnership may not
              require the Series Three Preferred Units to be redeemed.

          (d) The Assignee of any Limited Partner pursuant to Section 11 of the
              main part of the Partnership Agreement may exercise the rights of
              such Limited Partner pursuant to this Section 5, and such Limited
              Partner shall be deemed to have assigned such rights to such
              Assignee and shall be bound by the exercise of such rights by the
              Assignee. In connection with any exercise of such rights by an
              Assignee of a Limited Partner, the cash amount shall be paid by
              the Partnership directly to such Assignee and not to such Limited
              Partner.

          (e) A Redemption Notice shall be provided in the manner provided in
              Section 12. Any defect in a Redemption Notice or in the mailing
              thereof to any particular holder, the Partnership or the General
              Partner shall not affect the sufficiency of the notice or the
              validity of the proceedings for redemption with respect to the
              other holders. Any notice that was

                                       12
<PAGE>
 
              mailed in the manner herein provided shall be conclusively
              presumed to have been duly given on the date of deemed delivery
              provided in Section 12, whether or not the holder receives the
              notice. Each of the General Partner's Redemption Notices shall
              state, as appropriate: (1) the Option Strike Date; (2) the number
              of Series Three Preferred Units to be redeemed in the aggregate
              from all holders and, if fewer than all the Series Three Preferred
              Units held by such holder are to be redeemed, the number of such
              Series Three Preferred Units to be redeemed from such holder; and
              (3) that distributions on the Series Three Preferred Units to be
              redeemed shall cease to accrue on such Option Strike Date except
              as otherwise provided herein. Notice having been delivered as
              aforesaid, from and after the Option Strike Date (unless the
              Partnership shall fail to pay the redemption price on the date
              required), (i) except as otherwise provided herein, distributions
              on the Series Three Preferred Units so called for redemption shall
              cease to accrue, (ii) said Units shall no longer be deemed to be
              outstanding, and all rights of the holders thereof as holders of
              Series Three Preferred Units of the Partnership shall cease
              (except the right to receive the redemption price and the amounts
              required to be paid under subsection (c)).

              After the redemption of Series Three Preferred Units as
              aforesaid, the Partnership shall deliver to such holder, upon his
              written request, a certificate of the General Partner certifying
              the number of Common Units and Series Three Preferred Units held
              by such person immediately after such redemption. The Partnership
              shall also advise each holder as to the number of Series Three
              Preferred Units redeemed and the number of Series Three Preferred
              Units which remain outstanding.

          (f) Each Series Three Preferred Unit holder covenants and agrees with
              the Partnership that all Series Three Preferred Units delivered
              for redemption pursuant to this Section 5 shall be delivered to
              the Partnership free and clear of all liens, and, notwithstanding
              anything contained herein to the contrary, the Partnership shall
              not be under any obligation to acquire Series Three Preferred
              Units which are subject to any liens.

     (6)  The rights of each Series Three Preferred Unit holder pursuant to this
          Certificate arise solely from its ownership as a Limited Partner of
          Partnership Interests in the Partnership and not from it being a
          creditor of the Partnership and none of such rights with respect to
          any required redemption shall constitute a "claim" as such term is
          defined in Section 101 of the United States Bankruptcy Code as in
          effect as of the date of this Certificate; provided, however, that any
          rights in respect of such Series Three Preferred Units shall
          constitute equity interests of each Partner hereunder, it being agreed
          and understood that no

                                       13
<PAGE>
 
          Partner is waiving any equity interest it has in the Partnership or
          any rights to assert any such interests in any bankruptcy proceeding
          or otherwise.

     (7)  Conversion.  Holders of the Series Three Preferred Units shall have 
          ----------
          the right (the "Conversion Right") to convert all or a portion of such
          Units into Common Units (provided, however, that a holder may not
          exercise the Conversion Right for less than one thousand (1,000)
          Series Three Preferred Units or, if such holder holds less than one
          thousand Series Three Preferred Units, all of the Series Three
          Preferred Units held by such holder), and the General Partner shall
          have the right on each Option Strike Date to cause a conversion of
          Series Three Preferred Units into Common Units, subject, in each case,
          to the following conditions and procedures:

          (a)  Subject to and upon compliance with the provisions of this
               Section 7, a holder of Series Three Preferred Units shall have
               the right, at his or her option, at any time and from time to
               time during the period on or after the earlier of (i) December
               31, 2002 and (ii) the effective time of a Cash Business
               Combination (the period beginning on and after the earlier of
               such dates, the "Conversion Period"), to convert such Units into
               the number of fully paid and non-assessable Common Units obtained
               by dividing the aggregate Liquidation Preference of such Series
               Three Preferred Units by the Conversion Price as in effect as of
               such time (i.e. after adjustment as described in subsection (g))
               by delivering a Conversion Notice in the form attached hereto as
               Exhibit A within the time period specified in paragraph (d) below
               and in the manner provided in Section 12; provided, however, that
               the right to deliver a conversion notice with respect to Series
               Three Preferred Units called or tendered for redemption pursuant
               to Section 5 hereof shall terminate on that day which is the
               fifth business day prior to the applicable Option Strike Date on
               which such Units are to be redeemed, unless the Partnership shall
               default in making any cash payment required upon a redemption on
               such date as provided in Section 5 hereof. A conversion of Series
               Three Preferred Units specified in the Conversion Notice shall
               occur automatically at the close of business on the applicable
               Conversion Date without any action on the part of the holders of
               Series Three Preferred Units, and immediately after the close of
               business on the Conversion Date the holders of Series Three
               Preferred Units who had all or a portion of their Series Three
               Preferred Units converted shall be credited on the books and
               records of the Partnership with the issuance as of the opening of
               business on the next day of the Common Units issuable upon such
               conversion.

                                       14
<PAGE>
 
          (b)  If, as of an applicable Option Strike Date, the Target Amount for
               such Option Strike Date has not been redeemed and/or converted
               (or noticed for conversion and/or redemption on such Option
               Strike Date) as a result of Series Three Preferred Unit holders
               and/or the General Partner exercising Redemption Rights pursuant
               to Section 5 and/or such holders exercising their conversion
               rights pursuant to this Section 7, the Partnership, at the
               election of the General Partner and subject to and upon
               compliance with the provisions of this Section 7, may convert (a
               "Forced Conversion") not more than the lesser of (A) the Target
               Amount in respect of such Option Strike Date or (B) such number
               of Series Three Preferred Units as shall have an aggregate
               Liquidation Preference equal to the excess of (i) the aggregate
               Liquidation Preference of the sum of the Target Amounts for all
               prior Option Strike Dates and the currently applicable Option
               Strike Date over (ii) the aggregate Liquidation Preference of all
               Series Three Preferred Units previously converted, noticed for
               conversion by the holders on such Option Strike Date, previously
               redeemed, and noticed for redemption on such Option Strike Date
               (the "Forced Conversion Amount") of Series Three Preferred Units
               into a number of Common Units determined in accordance with the
               Conversion Price in effect on such date as determined in
               accordance with subsection (a) by transmitting for delivery a
               Conversion Notice, in the manner prescribed in Section 12 within
               one business day after the applicable Option Strike Date, to the
               holders of the Series Three Preferred Units which are to be so
               converted (the "Forced Conversion Option") ratably in proportion
               to the Series Three Preferred Units then outstanding from the
               holders thereof (after giving effect to the redemptions and
               conversions otherwise noticed to occur on such Option Strike
               Date); provided, further, however, that such Forced Conversion
               Option may only be exercised by the Partnership if the value of
               the REIT Shares, calculated on their weighted average closing
               price during the 10 Trading Days prior to the second Trading Day
               preceding the exercise of the Forced Conversion Option, is equal
               to or greater than 110% of the Conversion Price.

          (c)  Immediately prior to any conversion of Series Three Preferred
               Units, the Partnership shall pay, in cash, all accumulated and
               unpaid distributions including the further preferential
               distributions provided in Section 3(f) through the Conversion
               Date on all Series Three Preferred Units. A holder of Series
               Three Preferred Units shall have no right with respect to any
               Series Three Preferred Units so converted to receive any
               distributions paid after the Conversion Date with respect to such
               Series Three Preferred Units and his interest in the Partnership
               as to such converted Units shall be terminated; provided,
               however, that in the event the Partnership is legally or
               contractually prohibited from paying, or

                                       15
<PAGE>
 
               fails for any other reason to pay, such accumulated and unpaid
               distributions prior to any conversion and such holder elects to
               continue with and permit such conversion after notice from the
               Partnership of such inability or failure, such holder shall still
               be entitled to receive all such accumulated and unpaid
               distributions, if any, that remain unpaid after such conversion,
               as well as a further preferential distribution on such unpaid
               distributions as provided in Section 3(f), which distributions
               shall be paid by the Partnership as soon as it is legally and
               contractually permitted to do so.

          (d)  After the conversion of Series Three Preferred Units as 
               aforesaid, the Partnership shall deliver to such holder, upon his
               written request, a certificate of the General Partner certifying
               the number of Common Units and Preferred Units held by such
               person immediately after such conversion.

               Each conversion shall be deemed to have been effected immediately
               prior to the close of business on the date (the "Conversion
               Date") specified in the Conversion Notice (which shall not be
               earlier than 5 days after mailing of the Conversion Notice nor
               later than sixty (60) days after such date) or upon the Option
               Strike Date in the case of a Forced Conversion pursuant to
               Section 7(b) and the Series Three Preferred Units so presented
               for conversion shall be deemed converted into Common Units at the
               close of business on such date, and such conversion shall be in
               accordance with the Conversion Price in effect on such date
               (unless such day is not a Business Day, in which event such
               conversion shall be deemed to have become effective at the close
               of business on the next succeeding Business Day) as determined in
               accordance with subsection (a).

          (e)  No fractions of Common Units shall be issued upon conversion of
               the Series Three Preferred Units. Instead of any fractional
               interest in a Common Unit that would otherwise be deliverable
               upon the conversion of a Series Three Preferred Unit, the
               Partnership shall pay to the holder of such Series Three
               Preferred Unit an amount in cash based upon the Current Market
               Price of Common Units on the Trading Day immediately preceding
               the date of conversion. If more than one Series Three Preferred
               Unit shall be surrendered for conversion at one time by the same
               holder, the number of full Common Units issuable upon conversion
               thereof shall be computed on the basis of the aggregate number of
               Series Three Preferred Units so surrendered.

          (f)  The Assignee of any Limited Partner pursuant to Section 11 of the
               main part of the Partnership Agreement may exercise the rights 
               of such

                                       16
<PAGE>
 
               Limited Partner pursuant to this Section 7, and such Limited
               Partner shall be deemed to have assigned such rights to such
               Assignee and shall be bound by the exercise of such rights by the
               Assignee.

          (g)  The Conversion Price shall be adjusted from time to time as
               follows:

               (i)  If the Partnership shall after the Issue Date (A) pay or
                    make a distribution to holders of its Common Units in Common
                    Units, (B) subdivide its outstanding Common Units into a
                    greater number of Common Units, (C) combine its outstanding
                    Common Units into a smaller number of Common Units or (D)
                    issue any Common Units by reclassification of its Common
                    Units, the Conversion Price in effect at the opening of
                    business on the day following the date fixed for the
                    determination of Common Unit holders entitled to receive
                    such distribution or at the opening of business on the day
                    following the day on which such subdivision, combination or
                    reclassification becomes effective, as the case may be,
                    shall be adjusted so that the holder of any Series Three
                    Preferred Unit thereafter surrendered for conversion shall
                    be entitled to receive the number of Common Units that such
                    holder would have owned or have been entitled to receive
                    after the happening of any of the events described above had
                    such Series Three Preferred Units been converted immediately
                    prior to the record date in the case of a distribution or
                    the effective date in the case of a subdivision,
                    combination, or reclassification. An adjustment made
                    pursuant to this subsection (g)(i) shall become effective
                    immediately after the opening of business on the day next
                    following the record date in the case of a distribution and
                    shall become effective immediately after the opening of
                    business on the day next following the effective date in the
                    case of a subdivision, combination, or reclassification and
                    automatically without any further required action of the
                    Partnership or the Series Three Preferred Unit holders.

               (ii) If the Partnership shall issue after the Issue Date rights,
                    options or warrants to all holders of Common Units entitling
                    them to subscribe for or purchase Common Units (or
                    securities convertible into or exchangeable for Common
                    Units) at a price per Common Unit less than the Fair Market
                    Value per Common Unit on the record date for the
                    determination of Common Unit holders entitled to receive
                    such rights, options or warrants, then the Conversion Price
                    in effect at the opening of business on the day next
                    following such record date shall be adjusted to equal the
                    price determined by multiplying (I) the Conversion Price in
                    effect

                                       17
<PAGE>
 
                    immediately prior to the opening of business on the day
                    following the record date fixed for such determination by
                    (II) a fraction, the numerator of which shall be the sum of
                    (A) the number of Common Units outstanding on the close of
                    business on the record date fixed for such determination and
                    (B) the number of Common Units that the aggregate proceeds
                    to the Partnership from the exercise of such rights, options
                    or warrants for Common Units would purchase at such Fair
                    Market Value, and the denominator of which shall be the sum
                    of (A) the number of Common Units outstanding on the close
                    of business on the date fixed for such determination and (B)
                    the number of additional Common Units offered for
                    subscription or purchase pursuant to such rights, options or
                    warrants. Such adjustment shall become effective immediately
                    upon the opening of business on the day next following such
                    record date (subject to paragraph (l) below). In determining
                    whether any rights, options or warrants entitle the holders
                    of Common Units to subscribe for or purchase Common Units at
                    less than such Fair Market Value, there shall be taken into
                    account any consideration received by the Partnership upon
                    issuance and upon exercise of such rights, options or
                    warrants, the value of such consideration, if other than
                    cash, to be determined in good faith by the General Partner.

              (iii) If the Partnership shall distribute to all holders of its
                    Common Units any Partnership Units (other than Common Units)
                    or evidence of its indebtedness or assets (excluding cash
                    distributions to the extent that after giving effect to such
                    distributions the fair market value of the assets of the
                    Partnership exceed the sum of the liabilities of the
                    Partnership, as determined in good faith by the General
                    Partner) or rights or warrants to subscribe for or purchase
                    any of its securities (excluding those rights and warrants
                    issued to all holders of Common Units entitling them to
                    subscribe for or purchase Common Units or securities
                    convertible into or exchangeable for Common Units, which
                    rights and warrants and convertible or exchangeable
                    securities are referred to in and treated under subparagraph
                    (ii) above) (any of the foregoing being hereinafter in this
                    subparagraph (iii) called the "Securities"), then in each
                    case the Conversion Price shall be adjusted so that it shall
                    equal the price determined by multiplying (I) the Conversion
                    Price in effect immediately prior to the close of business
                    on the date fixed for the determination of Unit holders
                    entitled to receive such distribution by (II) a fraction,
                    the numerator of which shall be the Fair Market Value per
                    Unit of the Common Units on the record

                                       18
<PAGE>
 
                    date mentioned below less the then fair market value (as
                    determined by the General Partner in good faith) of the
                    portion of the Units or assets or evidences of indebtedness
                    so distributed or of such rights or warrants applicable to
                    one Common Unit, and the denominator of which shall be the
                    Fair Market Value per Unit of the Common Units on the record
                    date mentioned below. Such adjustment shall become effective
                    immediately upon the opening of business on the day next
                    following the record date for the determination of Unit
                    holders entitled to receive such distribution (subject to
                    paragraph (l) below). For the purposes of this subparagraph
                    (iii), the distribution of a Security, which is distributed
                    not only to the holders of the Common Units on the date
                    fixed for the determination of Unit holders entitled to such
                    distribution of such Security, but also is required to be
                    distributed with each Common Unit delivered to a person
                    converting a Series Three Preferred Unit after such
                    determination date, shall not require an adjustment of the
                    Conversion Price pursuant to this subparagraph (iii);
                    provided that on the date, if any, on which a person
                    converting a Series Three Preferred Unit would no longer be
                    entitled to receive such Security with a Common Unit (other
                    than as a result of the termination of all such Securities),
                    a distribution of such Securities shall be deemed to have
                    occurred, and the Conversion Price shall be adjusted as
                    provided in this subparagraph (iii) (and such day shall be
                    deemed to be "the date fixed for the determination of the
                    Unit holders entitled to receive such distribution" and "the
                    record date" within the meaning of the two preceding
                    sentences).

               (iv) Notwithstanding the foregoing, no adjustment shall be made
                    pursuant to the preceding clauses (ii) and (iii) that would
                    result in any increase in the Conversion Price. No
                    adjustment in the Conversion Price shall be required unless
                    such adjustment would require a cumulative increase or
                    decrease of at least 1% in such price; provided, however,
                    that any adjustments that by reason of this subsection
                    (g)(iv) are not required to be made shall be carried forward
                    and taken into account in any subsequent adjustment until
                    made; and provided, further, that any adjustment shall be
                    required and made in accordance with the provisions of this
                    Section 7 (other than this subsection (g)(iv)) not later
                    than such time as may be required in order to preserve the
                    tax-free nature of a distribution to the holders of Common
                    Units. Notwithstanding any other provisions of this Section
                    7, the Partnership shall not be required to make any
                    adjustment of the Conversion Price for the issuance of any
                    Common Units pursuant

                                       19
<PAGE>
 
                    to any employee benefit or compensation plan or other plan
                    providing for the reinvestment of distributions or interest
                    payable on securities of the Partnership and the investment
                    of additional optional amounts in Common Units under such
                    plan (or the issuance of any Common Units to the General
                    Partner in respect of a capital contribution by it resulting
                    from an analogous sale of its securities). All calculations
                    under this Section 7 shall be made to the nearest cent (with
                    $.005 being rounded upward) or to the nearest one-tenth of a
                    Unit (with .05 of a Unit being rounded upward), as the case
                    may be. Anything in this paragraph (g) to the contrary
                    notwithstanding, the Partnership shall be entitled, to the
                    extent permitted by law, to make such adjustments in the
                    Conversion Price (but without adversely affecting the
                    economic value of a Series Three Preferred Unit), in
                    addition to those required by this paragraph (g), as it in
                    its discretion shall determine to be advisable in order that
                    any Series Three Preferred Unit distributions, subdivision
                    of Series Three Preferred Units, reclassification or
                    combination of Series Three Preferred Units, distribution of
                    rights, options or warrants to purchase stock or securities,
                    or a distribution of other assets (other than cash
                    distributions) hereafter made by the Partnership to the
                    holders of the Series Three Preferred Units shall not be
                    taxable.

          (h)  If the Partnership or the General Partner shall be a party to any
               transaction (including without limitation a merger,
               consolidation, unit exchange, self tender offer for all or
               substantially all Common Units, sale of all or substantially all
               of the Partnership's assets or recapitalization of the Common
               Units and excluding any transaction as to which subparagraph
               (g)(i) of this Section 7 applies) (each of the foregoing being
               referred to herein as a "Transaction"), in each case as a result
               of which Common Units shall be exchanged for or converted into
               the right, or the holders of such Units shall otherwise be
               entitled, to receive securities or other property (including cash
               or any combination thereof), each Series Three Preferred Unit
               shall upon the commencement of the Conversion Period be
               convertible into the kind and amount of Units or securities and
               other property (including cash or any combination thereof) (the
               "Per Series Three Preferred Unit Merger Consideration")
               receivable upon the consummation of such Transaction by a holder
               of that number of Common Units into which one Series Three
               Preferred Unit was convertible immediately prior to such
               Transaction (unless, in connection with such Transaction, the
               Series Three Preferred Units had been converted into the right to
               receive such consideration (and thus, are no longer
               outstanding)), assuming such holder of Common Units is not a
               Person with which the Partnership consolidated or into which the

                                       20
<PAGE>
 
               Partnership merged or which merged into the Partnership or to
               which such sale or transfer was made, as the case may be (a
               "Constituent Person"), or an affiliate of a Constituent Person.
               In the event that holders of Common Units have the opportunity to
               elect the form or type of consideration to be received upon
               consummation of the Transaction, prior to such transaction the
               General Partner shall give prompt written notice to each Series
               Three Preferred Unit holder of such election, and each Series
               Three Preferred Unit holder shall also have the right to elect,
               by written notice to the General Partner, the form or type of
               consideration to be received upon conversion of each Series Three
               Preferred Unit held by such holder following consummation of such
               Transaction, and after such election the consideration thereby
               elected shall be the "Per Series Three Preferred Unit Merger
               Consideration" for each Series Three Preferred Unit held by such
               holder or any transferee thereof. If a holder of Series Three
               Preferred Units fails to make such an election, such holder (and
               any of its transferees) shall receive upon conversion of each
               Series Three Preferred Unit held by such holder (or by any of its
               transferees) the same Per Series Three Preferred Unit Merger
               Consideration that a holder of that number of Common Units into
               which one Series Three Preferred Unit was convertible immediately
               prior to such Transaction would receive if such Common Unit
               holder failed to make such an election.

                    The Partnership shall not be a party to any Transaction
               unless the terms of such Transaction are consistent with the
               provisions of this paragraph (h), and it shall not consent or
               agree to the occurrence of any Transaction until the Partnership
               has entered into an agreement with the successor or purchasing
               entity, as the case may be, for the benefit of the holders of the
               Series Three Preferred Units that will contain provisions
               enabling the holders of the Series Three Preferred Units that
               remain outstanding after such Transaction to convert their Series
               Three Preferred Units into the consideration provided for herein
               and that shall preserve the distribution preference, conversion,
               redemption, and other rights set forth in this Certificate.

          (i)   If:

               (i)  the Partnership shall declare a distribution on the Common
                    Units (excluding cash distributions to the extent that after
                    giving effect to such distributions the fair market value of
                    the assets of the Partnership exceed the sum of the
                    liabilities of the Partnership, as determined in good faith
                    by the General Partner); or

                                       21
<PAGE>
 
              (ii)  the Partnership shall authorize the granting to the holders
                    of the Common Units of rights or warrants to subscribe for
                    or purchase any Units of any class or any other rights or
                    warrants; or

             (iii)  there shall be any reclassification of the Common Units
                    (other than an event to which subparagraph (g)(i) of this
                    Section 7 applies) or any consolidation or merger to which
                    the Partnership is a party and for which approval of any
                    Unit holders of the Partnership is required, or a unit
                    exchange involving the conversion or exchange of Common
                    Units into securities or other property, or a self tender
                    offer by the Partnership for all or substantially all of its
                    outstanding Common Units, or the sale or transfer of all or
                    substantially all of the assets of the Partnership as an
                    entirety and for which approval of any Unit holders of the
                    Partnership is required; or

              (iv)  if there shall occur the voluntary or involuntary
                    liquidation, dissolution or winding up of the Partnership;

               then the Partnership shall cause to be mailed to the holders of
               the Series Three Preferred Units at their addresses as shown on
               the records of the Partnership, as promptly as possible, but at
               least 15 days prior to the applicable date hereinafter specified,
               a notice stating (A) the date on which a record is to be taken
               for the purpose of such distribution or granting of rights or
               warrants, or, if a record is not to be taken, the date as of
               which the holders of Common Units of record to be entitled to
               such distribution or granting of rights or warrants are to be
               determined or (B) the date on which such reclassification,
               consolidation, merger, unit exchange, sale, transfer,
               liquidation, dissolution or winding up is expected to become
               effective, and the date as of which it is expected that holders
               of Common Units of record shall be entitled to exchange their
               Common Units for securities or other property, if any,
               deliverable upon such reclassification, consolidation, merger,
               unit exchange, sale, transfer, liquidation, dissolution or
               winding up. Failure to give or receive such notice or any defect
               therein shall not affect the legality or validity of the
               proceedings described in this Section 7.

          (j)  In the event that a Cash Business Combination is to be 
               consummated or proposed to the holders of Common Units, the
               notice referred to in subparagraph (i)(iii) above shall specify
               such fact and such notice shall be mailed to the holders of the
               Series Three Preferred Units simultaneously with the mailing of
               notice to holders of Common Units of the holding of a meeting or
               written consent or making of elections with respect to the Cash
               Business Combination. In such event, the holders of

                                       22
<PAGE>
 
               Series Three Preferred Units shall be permitted to tender their
               Series Three Preferred Units for conversion, in accordance with
               Section 7 hereof, and may condition such tender upon the
               consummation of such Cash Business Combination. Any such
               conversion of Series Three Preferred Units shall happen
               simultaneously with the consummation of the Cash Business
               Combination such that holders of Series Three Preferred Units
               receive, at the consummation of the Cash Business Combination,
               the consideration described in Section 7(h).

          (k)  Whenever the Conversion Price is adjusted as herein provided, the
               Partnership shall promptly file in the books and records of the
               Partnership and provide to each holder an officer's certificate
               setting forth the Conversion Price after such adjustment as
               required by the terms hereof and setting forth a brief statement
               of the facts requiring such adjustment, which certificate shall
               be conclusive evidence of the correctness of such adjustment
               absent manifest error. Promptly after filing of such certificate,
               the Partnership shall prepare a notice of such adjustment of the
               Conversion Price setting forth the adjusted Conversion Price and
               the effective date such adjustment becomes effective and shall
               mail such notice of such adjustment of the Conversion Price to
               the holders of each Series Three Preferred Unit at such holder's
               last address as shown on the records of the Partnership.

          (l)  In any case in which paragraph (g) of this Section 7 provides 
               that an adjustment shall become effective on the day next
               following the record date for an event, the Partnership may defer
               until the occurrence of such event (A) issuing to the holder of
               any Series Three Preferred Unit converted after such record date
               and before the occurrence of such event the additional Common
               Units issuable upon such conversion by reason of the adjustment
               required by such event over and above the Common Units issuable
               upon such conversion before giving effect to such adjustment and
               (B) paying to such holder any amount of cash in lieu of any
               fractional Common Unit.

          (m)  There shall be no adjustment of the Conversion Price in case of
               the issuance of any Units in a reorganization, acquisition or
               other similar transaction except as specifically set forth in
               this Section 7. If any action would require adjustment of the
               Conversion Price pursuant to more than one paragraph of this
               Section 7, only one adjustment shall be made, and such adjustment
               shall be the amount of adjustment that has the highest absolute
               value; provided, however, that multiple actions taken at or about
               the same time shall be subject to separate adjustments.

                                       23
<PAGE>
 
          (n)  If the Partnership shall take any action affecting the Common
               Units, other than action described in this Section 7, that in the
               opinion of the General Partner would materially adversely affect
               the conversion rights of the holders of the Series Three
               Preferred Units, the Conversion Price for the Series Three
               Preferred Units may be adjusted, to the extent permitted by law,
               in such manner, if any, and at such time, as the General Partner,
               in its sole discretion, may determine to be equitable in the
               circumstances.

     (8)  Voting Rights.
          ------------- 

          (a)  Holders of the Series Three Preferred Units will not have any
               voting rights, except as set forth below or as otherwise from
               time to time required by law.

          (b)  So long as any Series Three Preferred Units remain outstanding,
               the Partnership shall not, without the affirmative vote of the
               holders of at least a majority of the Series Three Preferred
               Units outstanding at the time, given in person or by proxy,
               either in writing or at a meeting (voting separately as a class),
               amend, alter or repeal the provisions of the Partnership
               Agreement, increase the number of authorized Series Three
               Preferred Units or create any additional class or series of
               Preferred Units, whether by merger, consolidation or otherwise,
               so as to materially and adversely affect any right, preference,
               privilege or voting power of the Series Three Preferred Units or
               the holders thereof in their capacity as holders of Series Three
               Preferred Units; but subject, in any event, to the following
               provisions:

               (i)  With respect to the occurrence of any merger, consolidation
                    or other business combination or reorganization, so long as
                    the Series Three Preferred Units remain outstanding with the
                    terms thereof materially unchanged or, if the Partnership is
                    not the surviving entity in such transaction, are exchanged
                    for a security of the surviving entity with terms that are
                    materially the same with respect to rights to distributions,
                    voting, redemption and conversion as the Series Three
                    Preferred Units and without any income, gain or loss
                    expected to be recognized by the holder upon the exchange
                    for federal income tax purposes (and with the terms of the
                    Common Units or such other securities for which the Series
                    Three Preferred Units (or the substitute security therefor)
                    are convertible materially the same with respect to rights
                    to distributions, voting, redemption and conversion), the
                    occurrence of any such event shall not be deemed to
                    materially and adversely affect such rights, preferences,
                    privileges or voting powers of the holders of the Series
                    Three Preferred Units.

                                       24
<PAGE>
 
              (ii)  Any creation or issuance of any Common Units or of any class
                    or series of Preferred Units, in each case ranking junior to
                    the Series Three Preferred Units with respect to payment of
                    distributions, redemption rights and the distribution of
                    assets upon liquidation, dissolution or winding up, shall
                    not be deemed to materially and adversely affect such
                    rights, preferences, privileges or voting powers of the
                    holders of the Series Three Preferred Units.

             (iii)  Any creation or issuance of any series of Preferred Units
                    (other than an issuance of additional Series Three Preferred
                    Units, as to which a class vote shall be required; provided
                    that no class vote shall be required for any issuance of
                    Series Three Preferred Units in connection with or as
                    contemplated by any of the Source Agreements), or any
                    increase in the amount of authorized Units of such series,
                    in each case ranking on a parity with the Series Three
                    Preferred Units with respect to payment of distributions,
                    voting, redemption and the distribution of assets upon
                    liquidation, dissolution or winding up, shall not be deemed
                    to materially and adversely affect such rights, preferences,
                    privileges or voting powers of the holders of the Series
                    Three Preferred Units if such issuance is done (x) in
                    connection with an issuance of Partnership Units in exchange
                    for non-cash assets (including, without limitation, (i)
                    securities, partnership interests, membership interests or
                    other interests in an entity and (ii) real estate, personal
                    property and intangibles), or to the Company following the
                    issuance of securities by it for such non-cash assets and
                    the contribution of such non-cash assets to the Partnership
                    or (y) in connection with a bona fide capital raising
                    transaction or to the Company in consideration of a cash
                    contribution to the Partnership following a sale of
                    preferred stock by the General Partner in a bona fide
                    capital raising transaction.

               (iv) Any creation or issuance of any class or series of Preferred
                    Units ranking senior to the Series Three Preferred Units
                    with respect to the payment of distributions, redemption
                    rights and the distribution of assets upon liquidation,
                    dissolution or winding up, to the extent the issuance of
                    such Units was in compliance with the standard set forth in
                    Section 9(c) hereof, shall not be deemed to materially and
                    adversely affect such rights, preferences, privileges or
                    voting powers of the holders of the Series Three Preferred
                    Units.

                                       25
<PAGE>
 
                (c) In addition to the voting rights granted in paragraph (b)
                    above, the holders of Series Three Preferred Units shall be
                    entitled to vote at any time that the Limited Partners are
                    entitled to vote according to the Partnership Agreement. The
                    Series Three Preferred Units shall be entitled to vote the
                    same number of votes as the Common Units into which they may
                    be converted and shall vote with the Holders of Common Units
                    as a single class with the Common Units.

                (d) The foregoing voting provisions will not apply if, at or 
                    prior to the time when the act, with respect to which such
                    vote would otherwise be required, will be effected, all
                    outstanding Series Three Preferred Units shall have been
                    converted and/or redeemed.

     (9) Ranking.  The Series Three Preferred Units shall be deemed to rank:
         -------                                                            

                (a) Senior to any class or series of Units of the Partnership,
                    if such class or series shall be Common Units or if the
                    holders of Series Three Preferred Units shall be entitled to
                    receipt of distributions or of amounts distributable upon
                    liquidation, dissolution or winding up, as the case may be,
                    in preference or priority to the holders of Units of such
                    class or series, including Junior Preferred Units ("Junior
                    Units");

                (b) On a parity with the Series One Preferred Units, the Series 
                    Two Preferred Units and with any other class or series of
                    Units of the Partnership, if the holders of such other class
                    or series of Unit and the Series Three Preferred Units shall
                    be entitled to the receipt of distributions and of amounts
                    distributable upon liquidation, dissolution or winding up in
                    proportion to their respective amounts of accrued and unpaid
                    distributions per Unit or liquidation preferences, without
                    preference or priority one over the other ("Parity Units");
                    and

                (c) Junior only to (I) any indebtedness issued by the
                    Partnership and (II) senior preferred units issued only to
                    the General Partner having the same distribution rate, term,
                    preferences and other material terms (including conversion
                    rights) as preferred shares of stock (A) issued only for
                    cash by the General Partner in a public offering, or (B)
                    issued only for cash or property in an arm's length
                    transaction (x) to one or more institutional investors who
                    are (but for the preferred shares so issued) not affiliated
                    with the Partnership, the General Partner or any Affiliate
                    (as defined in Section 10) thereof and (y) not in connection
                    with any other transaction or transactions with any of such
                    Affiliates and (z) which would be permitted by Section 10 if
                    such preferred shares were Junior Preferred Units, and (C)
                    in either case, the entire cash proceeds (net of any arm's
                    length commissions paid to third parties who are not
                    Affiliates) of which

                                       26
<PAGE>
 
                    are contributed by the General Partner to the Partnership
                    and used by the Partnership solely for (i) the acquisition
                    of assets to be held in the Partnership's business, (ii)
                    capital expenditures or maintenance expenses in respect of
                    assets held by the Partnership, (iii) other ordinary course
                    expenses of the Partnership, or (iv) repayment of
                    indebtedness of the Partnership (including indebtedness
                    convertible into Junior Preferred Units or Common Units),
                    and (v) none of which proceeds are used (AA) to purchase,
                    redeem, retire or otherwise acquire directly or indirectly
                    any Junior Preferred Units or Common Units, or shares of
                    preferred stock junior to the Series A Preferred Stock of
                    the General Partner, or common stock of the General Partner,
                    or options, warrants, rights to purchase or any other
                    securities convertible into the foregoing (other than debt
                    repayable pursuant to subclause (iv)) or (BB) to make
                    distributions or to pay dividends in respect of any
                    securities described in subclause (AA). Any references to
                    the term "Affiliate" in this Section 9(c) (including by way
                    of the cross-reference and incorporation in clause (z) of
                    the preceding sentence) shall have the meaning given thereto
                    in the Amended and Restated By-laws of the General Partner
                    as of the date hereof (except that the 5% threshold referred
                    to therein shall be deemed for these purposes to be a 10%
                    threshold).

     (10) Junior Preferred Units.  The Partnership may, at its option, issue
          ----------------------                                            
          Junior Preferred Units in exchange for arm's length consideration, the
          adequacy of such consideration to be determined in good faith by the
          Board of Directors of the General Partner; provided, however, that the
          Partnership may not, without the consent of holders of a majority of
          the Series Three Preferred Units, (i) issue Junior Preferred Units to
          any Affiliate (as such term is defined in the Amended and Restated By-
          Laws of the General Partner as of the date hereof) of the General
          Partner or the Partnership, (ii) distribute Junior Preferred Units to
          any holder of Common Units, (iii) issue Junior Preferred Units ratably
          to holders of Common Units for cash or any other consideration, or
          (iv) issue Junior Preferred Units in exchange for Common Units.
          Notwithstanding the foregoing, in connection with the General
          Partner's issuance of preferred shares of stock, the Partnership may
          issue Junior Preferred Units to the General Partner having the same
          distribution rate, term, preferences and other material terms as such
          preferred shares, provided the issuance of such preferred shares would
          not violate this Section 10 if such shares were Junior Preferred Units
          and such issuance would comply with the requirements of Section 9 (c)
          (II) if they were senior preferred shares (but without giving effect
          to the word "institutional" in clause (B)(x) of Section 9(c)(II)).

     (11) Allocation of Nonrecourse Debt.  The provisions of that certain Tax
          ------------------------------                                     
          Reporting Agreement (including but not limited to paragraphs 3 and 4
          thereof) dated the

                                       27
<PAGE>
 
          date hereof among the Partnership and such holders are hereby
          incorporated herein by reference.

     (12) Notices.  All notices, demand, requests or other communications which
          -------                                                              
          may be or are required to be given, served or sent hereunder will be
          in writing and delivered by certified U.S. mail, return receipt
          required, with postage prepaid, or by nationally recognized overnight
          courier service that provides tracking and proof of receipt. Notices
          shall be deemed delivered upon the earlier of (i) delivery, (ii)
          refusal of delivery by addressee, (iii) two Business Days after
          deposit in the U.S. Mails in the case of certified U.S. mail, or (iv)
          one Business Day after deposit with a nationally recognized overnight
          courier. Notices to Series Three Preferred Unit holders shall be sent
          to their address of record with the Partnership. Any Series Three
          Preferred Unit holder may change its address of record by written
          notice as given as aforesaid. Notices delivered to the Partnership
          shall be addressed to Boston Properties Limited Partnership, Attn.:
          Chief Financial Officer, 8 Arlington Street, Boston, MA 02116 or to
          such other address as the Partnership may have notified holders in the
          manner provided in this Section 12. Notices to be delivered to the
          General Partner shall be addressed to Boston Properties, Inc., Attn:
          Chief Financial Officer, 8 Arlington Street, Boston, MA 02116, or to
          such other address as the General Partner may have notified holders in
          the manner provided in this Section 12.

     (13) Section 8.6.C of Partnership Agreement.  The provisions of Section 
          -------------------------------------- 
          8.6.C of the main part of the Partnership Agreement shall not apply to
          Series Three Preferred Units tendered or required to be tendered
          pursuant to Section 5, which shall control over any other provision of
          the Partnership Agreement. The provisions of Section 8.6.C of the
          Partnership Agreement also shall not apply to any Common Units that
          may be issued upon a conversion of Series Three Preferred Units
          ("Conversion Units"). For clarity, it is noted that the effect of this
          provision is that the restriction on the Redemption Right set forth in
          Section 8.6.C of the main part of the Partnership Agreement shall not
          apply to Conversion Units such that if a holder of a Conversion Unit
          presents a Conversion Unit for redemption and the delivery of REIT
          Shares to such holder is prohibited under the Certificate of
          Incorporation of the Company because such delivery would cause such
          holder to violate the Ownership Limit, then (i) the Company may not
          exercise its rights under Section 8.6.B to acquire such Conversion
          Unit for the REIT Shares Amount unless the Company waives or modifies
          the Ownership Limit applicable to such holder and (ii) if the Company
          does not so waive or modify the Ownership Limit then the Partnership
          must pay such holder the applicable Cash Amount to redeem such
          holder's Conversion Unit.

     (14) In the event this Certificate of Designations is amended or modified
          by the parties hereto, the holders of the Series Two Preferred Units
          issued by the

                                       28
<PAGE>
 
          Partnership and the Series A Preferred Stock issued by the General
          Partner in accordance with the Source Agreements shall each have the
          right to elect, by vote of a majority-in-interest of such securities,
          to adopt amendments or modifications of their respective securities
          comparable to the amendments or modifications of this Certificate, and
          in the event of any modification or amendment of such securities, the
          holders of Series Three Preferred Units shall have the right to elect,
          by vote of a majority-in-interest of the Series Three Preferred Units,
          to adopt amendments or modifications of this Certificate of
          Designations comparable to amendments and modifications of such
          securities. The Partnership and the General Partner agree for the
          benefit of the holders of Series Three Preferred Units that neither of
          them shall permit the amendment or modification of such other
          securities without causing this Section 14 to be given full effect,
          and the Partnership and the General Partner shall take such action as
          is reasonably appropriate or necessary to give full effect to this
          Section 14.

                                       29
<PAGE>
 
     IN WITNESS WHEREOF, Boston Properties, Inc., as General Partner of the
Partnership, has caused this Certificate of Designations to become effective,
and the Partnership Agreement is hereby amended by giving effect to the terms
set forth herein.

                                    BOSTON PROPERTIES, INC.


                                    By: /s/ William J. Wedge
                                       ---------------------------------
                                    Name:  William J. Wedge
                                    Title: Senior Vice President 



                                       30
<PAGE>
 
             Exhibit A to the Certificate of Designations for the
                         Series Three Preferred Units


                    NOTICE OF ELECTION BY PARTNER TO CONVERT
                 SERIES THREE PREFERRED UNITS INTO COMMON UNITS


     The undersigned Series Three Preferred Unit holder hereby (i) elects to
convert the number of Series Three Preferred Units in Boston Properties Limited
Partnership (the "Partnership") set forth below into Common Units in accordance
with the terms of the Second Amended and Restated Agreement of Limited
Partnership of the Partnership and the Certificate of Designations relating to
the Series Three Preferred Units that is a part thereof; and (ii) directs that
any cash in lieu of fractional Common Units that may be deliverable upon such
conversion be delivered to the address specified below.  The undersigned hereby
represents, warrants, and certifies that the undersigned (a) has title to such
Series Three Preferred Units, free and clear of the rights or interests of any
other person or entity other than the Partnership; (b) has the full right,
power, and authority to cause the conversion of such Series Three Preferred
Units as provided herein; and (c) has obtained the consent or approval of all
persons or entities, if any, having the right to consent or approve such
conversion.


Name of Series Three Preferred Unit holder: ___________________________________
                                            (Please Print: Exact Name as 
                                            Registered with Partnership)


Date of this Notice: _____________________________________


Date the Series Three Preferred Units are to be converted: ________________/1/


Number of Series Three Preferred Units to be converted: ______________________



                                     _________________________________________ 
                                     (Signature of Limited Partner: Sign Exact
                                     Name as Registered with Partnership)


                                     _________________________________________  
                                     (Street Address)



                                     _________________________________________ 
                                     (City)          (State)        (Zip Code)


                                     Signature Guaranteed by:


                                     _________________________________________ 

-------------------
/1/ Not earlier than 15 days nor later than 60 days after the date this
Notice is deposited in the U.S. mails (certified mail, postage prepaid, return
receipt requested) or deposited with a nationally recognized overnight courier
guaranteeing next business day delivery.
 

                                       31
<PAGE>
 
             Exhibit B to the Certificate of Designations for the
                         Series Three Preferred Units


                    NOTICE OF ELECTION BY PARTNER TO REDEEM
                     SERIES THREE PREFERRED UNITS FOR CASH


     The undersigned Series Three Preferred Unit holder hereby (i) elects to
redeem the number of Series Three Preferred Units in Boston Properties Limited
Partnership (the "Partnership") set forth below for the redemption price
determined in accordance with the terms of the Second Amended and Restated
Agreement of Limited Partnership of the Partnership and the Certificate of
Designations (the "Certificate") relating to the Series Three Preferred Units
that is a part thereof; and (ii) directs that such redemption price be delivered
by certified check to the address specified below.  The undersigned hereby
represents, warrants, and certifies that the undersigned (a) has title to such
Series Three Preferred Units, free and clear of the rights or interests of any
other person or entity other than the Partnership; (b) has the full right,
power, and authority to cause the redemption of such Series Three Preferred
Units as provided herein; and (c) has obtained the consent or approval of all
persons or entities, if any, having the right to consent or approve such
redemption.  The undersigned hereby acknowledges that, except as provided in the
Certificate,  distributions on the Series Three Preferred Units to be redeemed
shall cease to accrue on the redemption date indicated below.


Name of Series Three Preferred Unit holder: ___________________________________
                                            (Please Print: Exact Name as 
                                            Registered with Partnership)


Date of this Notice: _____________________________________


Option Strike Date on which the
Series Three Preferred Units are to be redeemed: ______________________


Number of Series Three Preferred Units to be converted: ______________________



                                     _________________________________________ 
                                     (Signature of Limited Partner: Sign Exact
                                     Name as Registered with Partnership)


                                     _________________________________________  
                                     (Street Address)



                                     _________________________________________ 
                                     (City)          (State)        (Zip Code)


                                     Signature Guaranteed by:


                                     _________________________________________ 

 

Note:  Redemptions are subject to reduction and proration as provided in the
       Certificate of Designations and the Partnership Agreement in respect of
       the Series Three Preferred Units.

                                       32
