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                                                                  EXHIBIT 10.28

                         AMENDMENT AND REINSTATEMENT OF
                         AGREEMENT OF PURCHASE AND SALE

     This Amendment and Reinstatement of Agreement of Purchase and Sale (this
"Reinstatement"), dated effective March 14, 2002, is executed by and between
Mack-Cali Texas Property L.P., a Texas limited partnership ("Seller"), and
Centennial Acquisition Company, a Texas corporation and Ashwood American
Properties, Inc, a Texas corporation (collectively, "Purchaser").

     WHEREAS, Purchaser and Seller entered into that certain Agreement of
Purchase and Sale, having an effective date of December 14, 2001, which was
amended by letter agreement between Seller and Purchaser dated January 25, 2002
("Amendment No. 1"), letter from Seller to Purchaser dated February 12, 2002,
letter from Seller to Purchaser dated February 14, 2002, letter from Seller to
Purchaser dated February 19, 2002, letter from Seller to Purchaser dated
February 21, 2002, letter from Seller to Purchaser dated February 22, 2002,
letter from Seller to Purchaser dated February 25, 2002, letter from Seller to
Purchaser dated February 26, 2002, letter from Seller to Purchaser dated
February 27, 2002, letter from Seller to Purchaser dated February 28, 2002,
letter from Seller to Purchaser dated March 1, 2002, and letter from Seller to
Purchaser dated March 4, 2002 (as amended, the "Agreement");

     WHEREAS, by letter dated March 5, 2002 from Purchaser to Seller (the
"Termination Letter"), Seller terminated the Agreement;

     WHEREAS, Purchaser and Seller desire to reinstate and amend the Agreement
as hereinafter set forth;

     NOW, THEREFORE, for and in consideration of the mutual covenants of the
parties hereto, and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged and confessed by the parties, the
parties agree as follows:

1.   All capitalized terms not defined herein shall have the meaning ascribed to
     such term in the Agreement.

2.   Except as modified by this Reinstatement, the Agreement is hereby
     reinstated, ratified and confirmed and in full force and effect. In the
     event of a conflict between the terms of this Reinstatement and the
     Agreement, the terms of this Reinstatement shall control.

3.   The parties acknowledge that the initial Earnest Money Deposit was not
     returned to Purchaser pursuant to the Termination Letter and that Purchaser
     shall deposit the additional Earnest Money Deposit required by Section
     4.1(a) of the Agreement no later than 5:00 p.m. Eastern Time on March 20,
     2002, subject to the provisions of Paragraph 15 below.

4.   The second sentence of Section 3.1 of the Agreement and the second and
     fourth sentences of Section 4.1(a) of the Agreement are hereby deleted in
     their entirety and replaced with "[Intentionally deleted]."

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5.   Section 5.1(b) of the Agreement is hereby deleted in its entirety and
     replaced with "[Intentionally deleted]."

6.   Paragraph 1 of Amendment No. 1 is deleted in its entirety and all
     references to the Mezzanine Loan, Mezzanine Lender and Mezzanine Loan
     Documents in the Agreement or any amendment thereto are deleted in their
     entirety.

7.   Section 11.1 of the Agreement is amended such that, notwithstanding
     anything in Section 11.1 to the contrary, if all or a Significant Portion
     of any Project is destroyed or damaged by fire or other casualty, Purchaser
     shall have the option to either (a) terminate the Agreement with respect to
     all of the Projects whereupon the Earnest Money Deposit shall be returned
     to Purchaser and the Agreement shall be of no further force or effect,
     except for the Termination Surviving Obligations or (b) proceed to Closing
     with respect to all of the Projects in accordance with Section 11.1.

8.   Section 11.2 of the Agreement is revised such that notwithstanding anything
     in Section 11.2 to the contrary, in the event of any (a) condemnation or
     sale in lieu of condemnation of all or substantially all of any Project, or
     (b) condemnation or sale in lieu of condemnation the proceeds of which are
     greater than twenty percent (20%) of the allocated Purchase Price of any
     Project prior to Closing or that materially interferes with the operations
     of the Project, Purchaser shall have the option, to be exercised within
     fifteen (15) days after receipt of notice of such condemnation or sale, of
     either (i) electing to terminate the Agreement in its entirety, whereupon
     the Earnest Money Deposit shall be returned to Purchaser or (ii) proceed to
     Closing with respect to all of the Projects in accordance with Section
     11.2. To determine whether a condemnation affects greater than twenty
     percent (20%) of the allocated purchase price of a Project, the allocated
     purchase price shall be deemed to be equal to the Purchase Price multiplied
     by a fraction, the numerator of which equals the original principal amount
     of the Senior Loan (defined below) allocated to the relevant Project and
     the denominator of which equals the original principal amount of the Senior
     Loan.

9.   Section 13.1 of the Agreement is amended such that notwithstanding any
     provision in Section 13.1 to the contrary, any termination of the Agreement
     permitted under Section 13.1 must include all of the Projects.

10.  Sections 9.1(g) and 9.2(a)(vi) are hereby deleted and replaced by the
     following:

          "(g)  None of the Projects shall be an Affected Project."

11.  Section 9.2(c) is hereby deleted in its entirety and replaced with
     "[Intentionally deleted]."

12.  Section 9.2(d) is hereby deleted in its entirety and replaced with
     "[Intentionally deleted]."

13.  Section 9.2(b) is hereby deleted in its entirety and replaced with the
     following:

          "(b)  Notwithstanding Section 9.2(a) or any other provision in this
     Agreement to the contrary, if, on the Scheduled Closing Date, the
     conditions precedent to Purchaser's obligation to close have not been
     satisfied (and Purchaser has not waived, in writing, any unsatisfied
     conditions precedent) with respect to one or more of the Projects, then
     either:

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               (i)  Purchaser shall waive in writing any unsatisfied conditions
          precedent with respect to the Affected Project(s) and proceed to
          Closing on the original Scheduled Closing Date with respect to all of
          the Projects (or proceed to Closing even if all conditions precedent
          have not yet been satisfied, thereby waiving all such unsatisfied
          conditions precedent); or

               (ii) with respect to all of the Projects, the Closing shall be
          deferred until the fifteenth (15th) day after the Scheduled Closing
          Date (such 15-day period being referred to herein as the "CONDITIONS
          PRECEDENT CURE PERIOD" and the last day of such 15-day period being
          referred to herein as the "EXTENDED CLOSING DATE"), at which time
          Purchaser shall either (A) proceed to Closing on the Extended Closing
          Date with respect to all of the Projects if all conditions precedent
          relating thereto have been satisfied (or Purchaser may proceed to
          Closing even if all conditions precedent have not yet been satisfied,
          thereby waiving all such unsatisfied conditions precedent) or (B) if
          the conditions precedent have not yet been satisfied (or waived by
          Purchaser) with respect to the Affected Project(s), and if at any time
          prior to the date that is fifteen (15) days after the Extended Closing
          Date (such 15-day period being referred to herein as the "SECOND
          CONDITIONS PRECEDENT CURE PERIOD" and the last day of such 15-day
          period being referred to herein as the "SECOND EXTENDED CLOSING DATE")
          all of the conditions precedent for the Affected Project(s) are
          satisfied, Purchaser shall, on the date that is two (2) Business Days
          after receipt by Purchaser of notice from Seller of such satisfaction
          (and evidence thereof if not already received by Purchaser), proceed
          to Closing with respect to all of the Projects. If as of the Second
          Extended Closing Date the conditions precedent for the Affected
          Project(s) are not satisfied, either A) Purchaser shall proceed to
          Closing on the Second Extended Closing Date or B) this Agreement shall
          terminate effective as of 5:00 p.m. Eastern Time on the Second
          Extended Closing Date, whereupon the Earnest Money Deposit, together
          with all interest earned thereon, shall, subject to Section 15(d)
          below, be returned to Purchaser and, except with respect to the
          Termination Surviving Obligations, this Agreement shall be null and
          void and the parties shall have no further obligation to each other."

14.  Section 9.2(e) is hereby deleted in its entirety and replaced by the
     following:

          "(e) In the event of a termination of this Agreement under this
     Section 9.2, Purchaser shall have the right to receive, within five (5)
     Business Days thereafter, a refund of the Earnest Money Deposit, together
     with all interest which has accrued thereon, and except with respect to the
     Termination Surviving Obligations, this Agreement shall be null and void
     and the parties shall have no further obligations to each other. Nothing in
     this Section 9.2(e) is intended to supersede any of the provisions of
     Section 13.1."

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15.  Termination Rights.

     (a) Purchaser hereby acknowledges and agrees that the Evaluation Period and
     all time periods during which Purchaser was permitted to review and object
     to title and survey matters have expired, and Purchaser has no right to
     terminate the Agreement or receive a refund of the Earnest Money Deposit
     pursuant to Section 5.3(c) of the Agreement.

     (b) Notwithstanding the foregoing, if the lender that is providing
     Purchaser with mortgage financing for the purchase of the Property (the
     "Mortgage Lender") has not yet countersigned the commitment for the
     purchase-money loan (the "Senior Loan"), then Purchaser may terminate the
     Agreement by written notice delivered to Seller no later than 5:00 p.m.
     Eastern Time March 20, 2002.

     (c) In addition, if (i) Purchaser's proposed mezzanine lender (the
     "Mezzanine Lender") and the Mortgage Lender are unable to negotiate the
     terms of an intercreditor agreement (the "Intercreditor Agreement") or (ii)
     the Mezzanine Lender does not approve the terms of the documents evidencing
     and securing the Senior Loan (the "Senior Loan Documents") or (iii) the
     Mortgage Lender does not approve the terms of the documents evidencing and
     securing the Mezzanine Loan (the "Mezzanine Loan Documents") or (iv)
     Purchaser and the Mezzanine Lender are unable to finalize the Mezzanine
     Loan Documents, in each case prior to the Scheduled Closing Date, then the
     Agreement shall terminate as of 5:00 p.m. Eastern Time on the Scheduled
     Closing Date, subject to the rights of either Purchaser and/or Seller to
     extend the Scheduled Closing Date to the Extended Closing Date by written
     notice delivered to the other party prior to 5:00 p.m. Eastern Time on the
     Scheduled Closing Date and to further extend the Scheduled Closing Date
     from the Extended Closing Date to the Second Extended Closing Date by
     written notice delivered to the other party prior to 5:00 p.m. Eastern Time
     on the Extended Closing Date, as necessary, in order to finalize the
     Intercreditor Agreement, the Senior Loan Documents and/or the Mezzanine
     Loan Documents, as applicable, in which event, if any of the items set
     forth in clauses (i), (ii), (iii) or (iv) of this Paragraph 15(c) are not
     finalized by the Extended Closing Date or the Second Extended Closing Date,
     as applicable, this Agreement shall terminate as of 5:00 p.m. Eastern Time
     on the Extended Closing Date (subject to the foregoing extension right) or
     on the Second Extended Closing Date, as applicable, provided that the
     Agreement shall not terminate by reason of any matter set forth in clauses
     (i), (ii), (iii) or (iv) of this Paragraph 15(c) if Purchaser secures a
     source of funds in place of the Mezzanine Loan and the Closing is not
     delayed beyond the Scheduled Closing Date (or, if the Scheduled Closing
     Date has been properly extended as set forth above, beyond the Extended
     Closing Date or the Second Extended Closing Date, as applicable) as a
     result thereof.

     (d) In the event of any termination of the Agreement permitted by this
     Paragraph 15, Purchaser shall receive a refund of the Earnest Money
     Deposit, together with all interest that has accrued thereon (except that
     such refund shall not be made in the case of a termination pursuant to
     clause (iv) of Paragraph 15(c) unless Purchaser has acted reasonably and in
     good faith in the course of the negotiations of the Mezzanine Loan
     Documents), and, except with respect to the Termination Surviving
     Obligations, the Agreement shall be null and void and the parties shall
     have no further obligations to each other.

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     (e) Purchaser hereby represents and warrants that the deposits or other
     monies delivered (or to be delivered, in the case of the commitment fee, on
     or before the date that is five (5) days after acceptance by the Mortgage
     Lender of the loan application) by Purchaser to the Mortgage Lender in the
     total amount of $544,000 are not refundable for any reason except as
     expressly set forth in the loan application for the Senior Loan and that a
     true, correct and complete copy of the loan applications and addenda
     thereto confirming this are attached hereto as Schedule 6.

16.  The Scheduled Closing Date shall be April 15, 2002.

17.  Purchaser shall receive a credit in cash at Closing in the amount of
     $600,000.

18.  At or prior to Closing, Seller shall either complete the repairs and
     improvements described on Schedule 1 attached hereto in accordance with the
     contracts referenced therein, or Purchaser shall receive (a) a credit at
     Closing equal to the unpaid amount under each contract referenced in
     Schedule 1 and (b) an assignment of such contracts, each of which Purchaser
     shall also simultaneously assume.

19.  With respect to the Leases described on Schedule 2 attached hereto, Seller
     shall be responsible for the payment of the tenant improvement allowances,
     in the amounts set forth opposite such Leases described on Schedule 2, to
     the extent not paid as of the Closing. Seller shall indemnify and hold
     Purchaser harmless with respect to such tenant improvement allowances.
     Purchaser acknowledges that, notwithstanding the foregoing or anything to
     the contrary in Section 10.4(e) of the Agreement, Seller shall not be
     responsible for the payment of any tenant improvement allowance required by
     the Spengler Lease at the Republic Property, except to the extent set forth
     on Schedule 2 hereof, or for the payment of any Leasing Commission
     associated with such Lease and such obligations shall be assumed by
     Purchaser at Closing. This Paragraph 19 shall survive the Closing.

20.  With respect to the written violation notices attached hereto as Schedule
     3, Seller shall either complete the work which is the subject of such
     notices substantially in accordance with the contracts attached hereto as
     Schedule 4 or Purchaser shall receive (a) a credit at Closing equal to the
     unpaid amount under each contract attached hereto as Schedule 4 and (b) an
     assignment of such contracts, each of which Purchaser shall also
     simultaneously assume.

21.  Purchaser hereby agrees to the proposed Sanitary Sewer Easement that is
     attached as Schedule 5 hereto, which will benefit the Project located on
     the Metroport Property, with the changes marked on such attachment and no
     additional required changes, and will not unreasonably withhold its consent
     to such easement in the event that the grantor of such easement does not
     agree to make all of such marked changes.

22.  Except as modified and amended as set forth in this Reinstatement, the
     Agreement shall remain unmodified and in full force and effect.

23.  This Reinstatement may be executed in any number of counterparts, each of
     which shall be an original and all of such counterparts together shall
     constitute one and the same instrument.

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24.  To facilitate the execution of this Reinstatement, the parties may execute
     and deliver counterparts of this Reinstatement by telephone facsimile.

            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK.]

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     IN WITNESS WHEREOF, the parties have executed this Reinstatement as of the
day and year first above written.

                             SELLER:

                             MACK-CALI TEXAS PROPERTY L.P.

                             By:  Mack-Cali Sub XVII, Inc., its general
                                  partner

                                  By: /s/ Roger W. Thomas
                                     -----------------------------------------
                                  Name:  Roger W. Thomas
                                       ---------------------------------------
                                  Title: Executive Vice President and General
                                        --------------------------------------
                                  Counsel
                                  --------------------------------------------
                             PURCHASER:

                             CENTENNIAL ACQUISITON COMPANY

                             By: /s/ Steven H. Levin
                                ----------------------------------------------
                             Name:  Steven H. Levin
                             Title: President

                             ASHWOOD AMERICAN PROPERTIES, INC.

                             By: /s/ Grady Jordan, Jr.
                                ----------------------------------------------
                             Name:  Grady Jordan, Jr.
                             Title: President<Page>

                                                                   EXHIBIT 10.29

                       AMENDMENT TO AMENDED AND REINSTATED
                         AGREEMENT OF SALE AND PURCHASE

     THIS AMENDMENT TO AMENDED AND REINSTATED AGREEMENT OF SALE AND PURCHASE
(this "AMENDMENT") is entered into as of the 29th day of March, 2002, by and
between MACK-CALI TEXAS PROPERTY L.P., a Texas limited partnership ("SELLER"),
and CENTENNIAL ACQUISITION COMPANY, a Texas corporation, and ASHWOOD AMERICAN
PROPERTIES, INC., a Texas corporation (collectively, "PURCHASER").

     A.   Seller and Purchaser entered into that certain Agreement of Sale and
Purchase dated as of December 14, 2001, which was amended by letter agreement
between Seller and Purchaser dated January 25, 2002, letter from Seller to
Purchaser dated February 12, 2002, letter from Seller to Purchaser dated
February 14, 2002, letter from Seller to Purchaser dated February 19, 2002,
letter from Seller to Purchaser dated February 21, 2002, letter from Seller to
Purchaser dated February 22, 2002, letter from Seller to Purchaser dated
February 25, 2002, letter from Seller to Purchaser dated February 26, 2002,
letter from Purchaser to Seller dated February 27, 2002, letter from Seller to
Purchaser dated February 28, 2002, letter from Seller to Purchaser dated March
1, 2002, letter from Seller to Purchaser dated March 4, 2002, terminated by
letter from Seller to Purchaser dated March 5, 2002, and amended and reinstated
by Reinstatement and Amendment of Agreement of Sale and Purchase dated as of
March 14, 2002 (as amended and reinstated, the "PURCHASE AGREEMENT"). All
capitalized terms used but not defined herein shall have the meaning given such
terms in the Purchase Agreement.

     B.   Seller and Purchaser now desire to amend the Purchase Agreement as set
forth below.

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, Seller and Purchaser agree as
follows:

     1.   ESTOPPELS.

          (a)   EXHIBIT H to the Purchase Agreement is hereby deleted in its
entirety and replaced with EXHIBIT H attached hereto.

          (b)   The Second sentence of Section 7.2 of the Purchase Agreement is
hereby deleted in its entirety and replaced with the following:

     "Notwithstanding the foregoing, Seller agrees to request, no later than
     two (2) Business Days after receipt from Purchaser of completed estoppel
     certificates (prepared by Purchaser or Purchaser's mortgage lender using
     the form annexed hereto as EXHIBIT H), that each Major Tenant and other
     Tenant in such buildings execute an estoppel certificate, and Seller shall
     use good faith efforts to obtain same."

          (c)   The fourth and fifth sentences of Section 7.2 of the Purchase
Agreement are hereby amended to delete the references therein to Section 9.2(c).

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          (d)   The fifth sentence of Section 7.2 of the Purchase Agreement is
further amended to insert "or fifty (50) days before the Second Extended
Closing Date," before "and if the Senior Lender requires..."

          (e)   Purchaser agrees that Seller shall not be required to obtain a
new estoppel if the original estoppel certificate obtained by Seller does not
satisfy the requirements of the Purchase Agreement if the reason the estoppel is
unsatisfactory is that either Purchaser or Purchaser's mortgage lender has made
a mistake in the preparation thereof, and Purchaser further agrees that any such
estoppel certificate shall be deemed to constitute a satisfactory estoppel.

     2.   REAFFIRMATION. Except as modified by the Amendment, the Purchase
Agreement is hereby ratified and confirmed and in full force and effect. In the
event of a conflict between the terms of this Amendment and the Purchase
Agreement, the terms of this Amendment shall control.

     3.   COUNTERPARTS. This Amendment may be executed in any number of
counterparts, all of which taken together will constitute one and the same
Amendment, and the signature page of any counterpart may be removed therefrom
and attached to any other counterpart. This Amendment shall be legally binding
upon receipt by each party of the facsimile or the original signature of Seller
and of Purchaser.

                   [SIGNATURES FOLLOW ON NEXT SUCCEEDING PAGE]

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     IN WITNESS WHEREOF the parties have executed this Amendment as of the day
and year first above written.

                               PURCHASER:

                               CENTENNIAL ACQUISITION COMPANY

                               By: /s/ Steven H. Levin
                                  ----------------------------------------------
                               Name: Steven H. Levin
                               Title: President

                               ASHWOOD AMERICAN PROPERTIES, INC.

                               By: /s/ David S. Gruber
                                  ----------------------------------------------
                               Name: David S. Gruber
                               Title: Chairman

                               SELLER:

                               MACK-CALI TEXAS PROPERTY L.P.

                               By: Mack-Cali Sub XVII, Inc., its general partner

                                  By: /s/ Roger W. Thomas
                                     -------------------------------------------
                                  Name: Roger W. Thomas
                                  Title: Executive Vice President
                                         & General Counsel

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