<PAGE>
                                                                    EXHIBIT 10.1


         This ASSUMPTION AND AMENDMENT TO CHANGE IN CONTROL AGREEMENT is entered
into effective as of May 22, 2002, by and among EQUITY OFFICE PROPERTIES
MANAGEMENT CORP., a Delaware corporation ("EOPMC"); EQUITY OFFICE PROPERTIES
TRUST, a Maryland real estate investment trust (the "Trust"); EOP OPERATING
LIMITED PARTNERSHIP, a Delaware limited partnership ("EOP Partnership"); and
RICHARD D. KINCAID (the "Executive").

                                    RECITALS

         Reference is made to a certain Change in Control Agreement dated as of
September 1, 2001, by and among EOPMC, the Trust and Executive (the "Change In
Control Agreement").

         The parties wish to amend the Change in Control Agreement as
hereinafter described.

                             Statement of Agreement

         Therefore, for value received, the receipt and sufficiency of which are
hereby acknowledged, the parties hereto do hereby enter into this Assumption and
Amendment to Change in Control Agreement providing as follows:

1. EOP Partnership, being both the sole shareholder of EOPMC and the current
employer of Executive, does hereby expressly assume, from and after January 1,
2002, all obligations of Employer set forth in the Change in Control Agreement
as if it were named therein as the Employer for the period from and after such
date. In consideration for such assumption, EOPMC is hereby released from any
and all future liability under or pursuant to the Change in Control Agreement.


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2. Section 2.5(e) of the Change in Control Agreement shall be modified to read
as follows:

         (e)      The appointment after May 22, 2002 of a new Chief Executive
                  Officer for the Trust.

   and the paragraph currently identified as Section 2.5(e) shall be re-numbered
   as Section 2.5(f)


3. Except as aforesaid, the original terms and conditions of the Change in
Control Agreement are hereby re-affirmed and agreed to continue in full force
and effect.


                                      EQUITY OFFICE PROPERTIES MANAGEMENT CORP

                                      By:  /s/ STANLEY M. STEVENS
                                         ----------------------------
                                      Its: Executive Vice President
                                           --------------------------

                                      EQUITY OFFICE PROPERTIES TRUST

                                      By: /s/ SAMUEL ZELL
                                         ----------------------------
                                          Samuel Zell
                                          President and Chief Executive Officer

                                      EOP OPERATING LIMITED PARTNERSHIP

                                      By: Equity Office Properties Trust,
                                      Its General Partner

                                      By: /s/ SAMUEL ZELL
                                         ----------------------------
                                          Samuel Zell
                                          President and Chief Executive Officer


                                      /s/ RICHARD D. KINCAID
                                      -------------------------------
                                      Richard D. Kincaid






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