EXHIBIT 10.1

                                                              November 30, 1999

Reckson Service Industries Inc.
10 East 53rd Street
New York, New York 10022

                Re: Second Amended and Restated Credit Agreements

Dear Sirs:

     Reference is made to the Amended and Restated Credit Agreement, dated as of
August 4, 1999,  between  Reckson  Service  Industries,  Inc.,  as Borrower (the
"Borrower") and Reckson  Operating  Partnership,  L.P., as Lender (the "Lender")
relating to the operations of the Borrower (the "RSI Facility"), and the Amended
and Restated Credit Agreement,  dated as of August 4, 1999, between the Borrower
and the Lender relating to Reckson Strategic Venture Partners LLC (together with
the RSI Facility,  the "Credit  Facilities").  Capitalized terms used herein and
not  otherwise  defined  shall have the  meaning  ascribed  to such terms in the
Credit Facilities.

     You have  advised us of your  proposal to obtain (i) a $60 million  secured
loan from Warburg Dillon Read and UBS AG (or other lenders) substantially on the
terms set forth on the term sheet attached hereto as Exhibit A (the "Secured $60
million  Loan")  and (ii) a $75  million  secured  loan from  Reckson  Strategic
Venture Partners LLC (or other lenders)  substantially on the terms set forth in
the term sheet attached hereto as Exhibit B (the "Secured $75 million Loan" and,
together with the Secured $60 million Loan, the "Secured Loans").  You have also
advised us of your proposal to issue up to $200 million in preferred  stock (the
"Preferred Stock").




<PAGE>

1.   Amendments.  We hereby  agree to the  following  amendments  to the  Credit
     Facilities:

     a.   Section  1.1(b) is hereby  amended  to add the  following  definition:
          "Adjusted EBITDA" shall mean, for any fiscal quarter,  EBITDA less any
          amounts  payable (i) by any subsidiary in respect of the  Indebtedness
          of such  Subsidiary  (including,  but not limited to,  Indebtedness of
          VANTAS  Incorporated and the Secured $75 million Loan) and (ii) by the
          Borrower in respect of the Secured $60 million Loan.

     b.   The third  sentence of Section 3.1 of the Credit  Facilities is hereby
          amended by deleting  the  references  to "EBITDA" and  replacing  such
          references with the term "Adjusted EBITDA."

     c.   Section  7.2(c) of the Credit  Facilities is hereby amended to add the
          following:

          (iv) Indebtedness of the Borrower payable to its subsidiaries, partner
               companies  or other  companies  into  which  the  Borrower  makes
               investments  to evidence the  obligation  of the Borrower to fund
               future capital commitments into such entities.

2.   Consents. We hereby consent to the following:

     a.   The Liens to be granted  under the Secured Loans shall be deemed to be
          Permitted Liens for purposes of the Credit Facilities.

     b.   In accordance with Section  7.2(c)(iii) of the Credit Facilities,  the
          incurrence of Indebtedness  under the Secured Loans and the payment of
          interest thereon is hereby approved.

     c.   In  accordance   with  Sections   7.2(d)  and  7.2(e)  of  the  Credit
          Facilities,  the filing of one or more Certificates of Designation and
          any  amendments  thereto in respect of the  Preferred  Stock,  and the
          payment by the Borrower of  dividends to the holders of the  Preferred
          Stock, is hereby approved.

3.   Fees. It is understood  that a fee equal to 176,186 shares of common stock,
     par value $.01 per share, of the Borrower shall be paid to us upon delivery
     of this letter in consideration of the matters covered in this letter.

                           Very truly yours,

                           RECKSON OPERATING PARTNERSHIP, L.P.

                           By: Reckson Associates Realty Corp., general partner


                           By:
                              --------------------------------
                               Name:
                               Title:

Confirmed and Accepted:
RECKSON SERVICE INDUSTRIES, INC.


By:
   -------------------------------
   Name:
   Title:



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