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                                                                     EXHIBIT 4.1

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                         HALLWOOD REALTY PARTNERS, L.P.

                                       AND

                          EQUISERVE TRUST COMPANY, N.A.

                                 AS RIGHTS AGENT

                              --------------------

                             AMENDMENT NO. 3 TO THE

                         UNIT PURCHASE RIGHTS AGREEMENT

                          DATED AS OF NOVEMBER 30, 1990

                              DATED: APRIL 16, 2004

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                                 AMENDMENT NO. 3
                        TO UNIT PURCHASE RIGHTS AGREEMENT

      Amendment No. 3 made as of April 16, 2004 (the "Amendment") to the Unit
Purchase Rights Agreement, dated as of November 30, 1990, by and between
HALLWOOD REALTY PARTNERS, L.P., a Delaware limited partnership (the
"Partnership"), and EQUISERVE TRUST COMPANY, N.A., a national banking
association (formerly known as Bank Boston, N.A. and The First National Bank of
Boston, the "Rights Agent"), as amended by that certain Amendment No. 1 to the
Rights Plan, dated February 14, 2000, between the Partnership and the Rights
Agent, and that certain Amendment No. 2 to the Rights Plan, dated March 28,
2003, between the Partnership and the Rights Agent (as so amended, the "Rights
Plan").

      WHEREAS, the Partnership and the Rights Agent desire to amend certain
terms of the Rights Plan as set forth herein, pursuant to Section 26 of the
Rights Plan.

      NOW, THEREFORE, in consideration of the premises and the mutual agreements
herein set forth, the parties hereby agree as follows:

      1. Amendment. The Rights Plan is hereby amended as follows:

            (a) Section 1(a) is hereby amended to add the following sentence to
the end of such Section 1(a):

      "In addition, notwithstanding the foregoing, no Person shall be or become
      an Acquiring Person and no Distribution Date shall occur by reason of (A)
      the execution and delivery of the Agreement and Plan of Merger, dated as
      of April 16, 2004, by and among the Partnership, the General Partner, HRPT
      Properties Trust and a wholly-owned subsidiary of HRPT Properties Trust
      ("Merger Sub") (as it may be amended from time to time, the "Merger
      Agreement"), or the execution and delivery of any amendment thereto (B)
      the merger of the Partnership with Merger Sub pursuant to and in
      accordance with the provisions of the Merger Agreement (the "Merger"), (C)
      the performance or the consummation of any transaction contemplated by the
      Merger Agreement, (D) the execution and delivery of the Purchase
      Agreement, dated as of April 16, 2004, by and among HRPT Properties Trust
      and a wholly-owned subsidiary of HRPT Properties Trust, the General
      Partner, Hallwood Commercial Real Estate, LLC, HWG, LLC, HWG Realty
      Investors, LLC, HWG 95 Advisors, Inc., HWG 98 Advisors, Inc. and The
      Hallwood Group Incorporated, and any other parties signatory thereto (as
      it may be amended from time to time, the "Purchase Agreement"), or the
      execution and delivery of any amendment thereto, or (E) the performance or
      the consummation of any transaction contemplated by the Purchase
      Agreement."

            (b) Sections 1(n) and 1(o) are hereby re-designated as Sections 1(p)
and 1(q), Sections 1(p) through 1(x) are hereby re-designated as Sections 1(s)
through 1(aa), all references to those sections in the Rights Plan are
correspondingly amended, and new Sections 1(n), 1(o) and 1(r) shall be inserted
to read in their entirety as follows:
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            "(n) "Merger" shall have the meaning set forth in Section 1(a)
      hereof."

            "(o) "Merger Agreement" shall have the meaning set forth in Section
      1(a) hereof."

            "(r) "Purchase Agreement" shall have the meaning set forth in
      Section 1(a) hereof."

            (c) Section 3(b) is hereby amended to add the following sentence to
the end of such Section 3(b):

      "Notwithstanding anything to the contrary contained herein, no
      Distribution Date shall occur as a result of the approval, execution,
      delivery, announcement or performance of the Merger Agreement and/or the
      Purchase Agreement (or any amendment thereto in accordance with the terms
      thereof) or the consummation of the transactions contemplated thereby
      (including, without limitation, the Merger)."

            (d) Section 7(a) is hereby amended in its entirety to read as
follows:

      "The Rights shall not be exercisable until, and shall become exercisable
      on, the Distribution Date (unless otherwise provided herein). The Rights
      may be exercised, in whole or in part, at any time commencing with the
      Distribution Date upon surrender of the Right Certificate, with the form
      of election to purchase and certificate on the reverse side thereof duly
      executed (with signatures duly guaranteed), to the Rights Agent at the
      office of the Rights Agent designated for such purpose, together with
      payment of the Exercise Price with respect to each Right exercised,
      subject to adjustment as hereinafter provided, at or prior to the close of
      business on the earlier of (i) March 31, 2008, (ii) immediately upon the
      effective time of the Merger (the earlier of (i) and (ii) being referred
      to as the "Final Expiration Date") or (iii) the date on which the Rights
      are redeemed as provided in Section 23 hereof (such earlier date being
      herein referred to as the "Expiration Date")."

            (e) Section 11 is hereby amended to add the following to the end of
such Section 11:

            "(g) Notwithstanding anything to the contrary contained herein, the
      provisions of this Section 11 will not apply to, or become operable as a
      result of, the approval, execution, delivery, announcement or performance
      of the Merger Agreement and/or the Purchase Agreement (or any amendment
      thereto in accordance with the terms thereof) or the consummation of the
      transactions contemplated thereby (including, without limitation, the
      Merger)."

      2. The Rights Agreement, as amended hereby, shall remain in full force and
effect.

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      3. This Amendment shall be deemed a contract made under the laws of the
State of Delaware and for all purposes shall be governed and construed and
enforced in accordance with the laws of such state applicable to contracts made
and performed entirely within such state.

      4. If any term, provision, covenant or restriction of this Amendment is
held by a court of competent jurisdiction or other authority to be invalid, void
or unenforceable, the remainder of the terms, provisions, covenants and
restrictions of this Amendment and of the Rights Plan shall remain in full force
and effect and shall in no way be affected, impaired or invalidated.

      5. This Amendment may be executed in one or more counterparts, each of
which shall be deemed to be an original, but all of which shall constitute one
and the same agreement.

                            [SIGNATURE PAGE FOLLOWS]

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      IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 3 to
be duly executed, all as of the day and year first written above.

                                        HALLWOOD REALTY PARTNERS, L.P.

                                        By:    Hallwood Realty, L.L.C.
                                               General Partner

                                        By:    /s/ John G. Tuthill
                                               ---------------------------------
                                        Name:  John G./ Tuthill
                                        Title: Executive Vice President

                                        EQUISERVE TRUST COMPANY, N.A.

                                        By:    /s/ Carol Mulvey-Eori
                                               ---------------------------------
                                        Name:  Carol Mulvey-Eori
                                        Title: Managing DirectorExhibit 10.57

                     AMENDMENT NO. 1 TO AMENDED AND RESTATED
                              EMPLOYMENT AGREEMENT

                  AMENDMENT (this "Amendment") made as of March 8, 2004 by and
between Alamosa Holdings, Inc., a Delaware corporation ("Alamosa"), and David E.
Sharbutt (the "Employee"). This Amendment amends the Amended and Restated
Employment Agreement (the "Employment Agreement") made as of October 1, 2002
between Alamosa and the Employee.

         1. The Employment Agreement is hereby amended by restating the first
sentence of Section 4 in its entirety to read as
follows:

         Employee shall be eligible to receive an annual bonus, which shall have
         a target of $250,000.

         2. The Employment Agreement is hereby amended by restating the first
and second sentences of Section 6(b) in their entirety to read as follows:

         In addition, the Committee shall grant Employee additional options
         according to the following schedule: 2003 - 250,000 options, 2004 -
         425,000 options, 2005 - 300,000 options, 2006 - 240,000 options and
         2007 - 100,000 options. Except in respect of 2003, one half of the
         annual options will be granted in January and one half in July and for
         2004 one half of the annual options will be granted prior to July 2004.

         3. Employee hereby acknowledges that Exhibit A to the Employment
Agreement is attached as Exhibit A hereto.

         IN WITNESS WHEREOF, the parties have duly executed this Amendment
effective as of January 1, 2004.

                             ALAMOSA HOLDINGS, INC.

                             By: /s/ Kendall Cowan
                                 ------------------------------------------

                             EMPLOYEE

                             /s/ David E. Sharbutt
                             ----------------------------------------------

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