EXHIBIT 10.28

FIRST AMENDMENT TO REVOLVING CREDIT AGREEMENT

     This First Amendment to Revolving Credit Agreement (this “First Amendment”)
amends that certain Revolving Credit Agreement (as amended hereby, the “Credit
Agreement”) dated as of December 31, 2003, and is made and entered into as of
the 13th day of February, 2004 by and among FIRST POTOMAC REALTY INVESTMENT
LIMITED PARTNERSHIP (“FPLP” or the “Borrower”), FLEET NATIONAL BANK (“Fleet”), a
national banking association, having its principal place of business at 100
Federal Street, Boston, Massachusetts 02109 and KEYBANK NATIONAL ASSOCIATION
(collectively with Fleet, the “Banks”) and FLEET NATIONAL BANK, as managing
administrative agent for itself and each other Bank.

     WHEREAS, the Banks and the Borrower have determined to make certain
amendments to the Credit Agreement, as set forth herein.

     NOW, THEREFORE, in consideration of One Dollar ($1.00) and other good and
valuable consideration by each of the parties hereto, the receipt and
sufficiency of which are hereby acknowledged, it is agreed as follows:

1.   Capitalized terms used but not defined herein shall have the respective
meanings assigned to such terms in the Credit Agreement.   2.   The definition
of “Assignment of Contracts” contained in Section 1 of the Credit Agreement is
amended by inserting the word “in” immediately following the reference to
“Borrower’s interest” contained therein.   3.   The definition of “Borrowing
Base Availability” contained in Section 1 of the Credit Agreement is amended to
read in its entirety as follows:

    “Borrowing Base Availability. As of the date that any Loan is to be made
hereunder, an amount equal to the lesser of (i) 70 % (the “Advance Rate”) of the
Collateral Property Value at such time, provided that the Advance Rate shall be
automatically and permanently decreased to 65% at such time as the Collateral
Property Value multiplied by 65% would be at least equal to $50,000,000, and
(ii) the Collateral Debt Service Coverage Amount at such time, and provided,
further, that at no time may the Borrowing Base Availability otherwise
attributable to the Collateral Properties exceed 85% of the Appraised Value of
Collateral Properties as set forth in the most recent MAI Appraisals provided to
and approved by the Administrative Agent (it being acknowledged and agreed that
if the Borrowing Base Availability attributable to the Collateral Properties
would exceed 85% of the

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    Appraised Value of Collateral Properties, the Borrower may request that a
new MAI Appraisal be obtained for one or more Collateral Properties, at the
Borrower’s sole cost and expense, and the appraised value determined by such new
MAI Appraisal(s) shall then be the effective appraised value for the applicable
Collateral Properties for purposes of this definition. The amount available to
be drawn at any time shall be the Borrowing Base Availability less the Maximum
Drawing Amount and all outstanding Loans at such time.”

4.   The definition of “Eligible Assignee” contained in Section 1 of the Credit
Agreement is amended by inserting, at the end thereof, the following new
sentence:

    “In no event shall the Borrower or any Affiliate of the Borrower be an
Eligible Assignee.”

5.   Clause (c) of the definition of “Increase Conditions” contained in Section
1 of the Credit Agreement is amended by inserting the words “an Eligible
Assignee and” immediately following the words “such financial institution shall
be” contained therein.   6.   The definition of “Tenant Estoppel” contained in
Section 1 of the Credit Agreement is amended by deleting each reference to the
word “Major” contained therein and replacing it with the following: “Collateral
Property”.   7.   Clause (c) of Section 2.3 of the Credit Agreement is amended
by inserting the word “and” immediately following the first reference to
“Applicable Base Rate Margin” contained therein.   8.   Clause (v) of
Section 2.4 of the Credit Agreement is amended to read in its entirety as
follows:

    “The Agent will promptly notify each Lender of any Completed Loan Request
and will cause a copy thereof to be delivered to each Lender on the same
Business Day received, or, in the case of a Libor Rate Loan, the next Business
Day, in each case absent circumstances outside of its control.”

9.   Section 2.8 of the Credit Agreement is amended by deleting the reference to
“$20,000,000” contained therein; and by inserting in place thereof the
following: “$50,000,000.”

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10.   Clauses (c) and (d) contained in Section 8.4 of the Credit Agreement are
each amended by deleting therefrom the words: “Upon the request of the Agent
and”.   11.   Clause (a) contained in Section 11.4 of the Credit Agreement is
amended by inserting a comma immediately following the word “creation” contained
therein.   12.   Section 12.9 of the Credit Agreement is amended: (i) by
deleting the reference to “Estoppel Agreements” contained in clause (b) thereof
and replacing it with the words “Tenant Estoppels; and (ii) by inserting the
following at the end thereof: “, in each case except to the extent waived by the
Agent with respect to tenants who are not tenants under Major Leases”.   13.  
The parenthetical contained in Section 12.14 of the Credit Agreement is amended
by deleting the reference to “Appraisal Determination Process” contained
therein; and by inserting in place thereof the following words: “the definition
thereof.   14.   Clause (n) contained in Section 14.1 of the Credit Agreement is
amended by inserting at the end thereof the following:

    “; or during any twelve-month period on or after the Closing Date,
individuals who at the beginning of such period constituted the Board of
Trustees of the Trust (together with any new directors whose election by the
Board of Trustees or whose nomination for election by the shareholders of the
Trust was approved by a vote of at least a majority of the members of the Board
of Trustees then in office who either were members of the Board of Trustees at
the beginning of such period or whose election or nomination for election was
previously so approved) ceased for any reason to constitute a majority of the
members of the Board of Trustees of the Trust then in office.”

15.   The second and third sentences contained in Section 14.2 of the Credit
Agreement are amended to read in their entirety as follows:

    “If any other Event of Default shall have occurred and be continuing, the
Agent may, and upon the request of the Majority Lenders shall, terminate the
unused portion of the Commitments or other commitment to extend credit
hereunder. No such termination of the Commitments or other commitment to extend
credit hereunder shall relieve the Borrower of any of the Obligations or

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    any of its existing obligations to the Agent or the Lenders arising under
other agreements or instruments.”

16.   The seventh sentence contained in Section 16.10(b) of the Credit Agreement
is amended by inserting the following proviso at the end thereof:

    “, provided, however, that the Agent may not implement the proposed workout
plan without the Majority Lenders’ approval if the number of Lenders hereunder
is three or less.”

17.   The first sentence contained in Section 16.11 of the Credit Agreement is
amended by inserting at the end thereof the following:

    “and, at the request of the Majority Lenders, the Agent will resign if its
Commitment is no longer at least equal to that of the largest Commitment of any
Lender, unless such circumstance is a result of the merger or consolidation of
any of the other Lenders or a result of events other than the sale by the Agent
of any portion of its Commitment”.

18.   Section 16.11 of the Credit Agreement is further amended by inserting at
the end thereof the following new sentence:

    “The Agent may be removed at the direction of the Majority Lenders in the
event of a final judicial determination (in which the Agent had an opportunity
to be heard) that the Agent had acted in a grossly negligent manner or in
willful misconduct.”

19.   The third sentence contained in Section 18 of the Credit Agreement is
amended to add the following at the end thereof:

    “, provided that such consent shall not be required at any time that an
Event of Default has occurred and is continuing.”

20.   Schedule 2 to the Credit Agreement is amended to read in its entirety as
set forth on Annex 1 attached hereto.

21.   The Borrower hereby represents and warrants as follows:

(a) Representations in Credit Agreement. Both before and after giving effect to
this First Amendment, each of the representations and warranties made by or on
behalf of the Borrower, the Trust or any of their respective Subsidiaries
contained in the Credit Agreement or any of the other Loan Documents, was true
when made and is true on and as of the date hereof

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with the same full force and effect as if each of such representations and
warranties had been made on the date hereof and in this First Amendment, except
to the extent that such representations and warranties relate expressly to an
earlier date.

(b) No Events of Default. No Default or Event of Default exists on the date
hereof (both before and after giving effect to this First Amendment).

(c) Binding Effect of Documents. This First Amendment has been duly executed and
delivered by the Borrower and is in full force and effect as of the date hereof,
and the agreements and obligations of the Borrower contained herein constitute
legal, valid and binding obligations of the Borrower enforceable against the
Borrower in accordance with their respective terms.

22.   Provisions of General Application.

(a) No Other Changes. Except as otherwise expressly provided by this First
Amendment, all of the terms, conditions and provisions of the Credit Agreement
and each of the other Loan Documents remain unaltered. The Credit Agreement and
this First Amendment shall be read and construed as one agreement.

(b) Governing Law. This First Amendment is intended to take effect as a sealed
instrument and shall be deemed to be a contract under the laws of the State of
New York. This First Amendment and the rights and obligations of each of the
parties hereto shall be governed by and interpreted and determined in accordance
with the laws of the State of New York (without regard to conflicts of laws
provisions).

(c) Binding Effect; Assignment. This First Amendment shall be binding upon and
inure to the benefit of each of the parties hereto and their respective
successors in title and assigns.

(d) Counterparts. This First Amendment may be executed in any number of
counterparts, but all such counterparts shall together constitute but one and
the same agreement. In making proof of this First Amendment, it shall not be
necessary to produce or account for more than one counterpart thereof signed by
each of the parties hereto.

(e) Conflict with Other Agreements. If any of the terms of this First Amendment
shall conflict in any respect with any of the terms of any of the Credit
Agreement or any other Loan Document, the terms of this First Amendment shall be
controlling.

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(f) Condition Precedent. The effectiveness of this First Amendment is subject to
the condition precedent that the Agent shall have received, in form and
substance satisfactory to it, an executed original of this First Amendment from
the Borrower, the Trust and each of the Lenders.

     WITNESS the execution hereof, under seal, as of the day and year first
written above.

                          FLEET NATIONAL BANK,             Individually and as
Managing Administrative Agent       -s- DANIEL L. SILBERT [w95659w9565900.gif]  
        By:

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          Name:  Daniel L. Silbert           Title:  Director        
 
                        KEYBANK NATIONAL ASSOCIATION, Individually       -s-
JOHN C. SCOTT [w95659w9565901.gif]           By:

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          Name:  John C. Scott           Title:  Vice President        
 
                        FIRST POTOMAC REALTY INVESTMENT LIMITED PARTNERSHIP  
 
                      By: First Potomac Realty Trust, its sole general partner  
      -s- BARRY H. BASS [w95659w9565902.gif]           By:

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            Name:  Barry H. Bass           Title:  Senior Vice President and CFO
   

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ACCEPTED AND AGREED:

FIRST POTOMAC REALTY TRUST, Guarantor

                          -s- BARRY H. BASS [w95659w9565902.gif]           By:

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 (SEAL)         Name:  Barry H. Bass           Title:  Senior Vice President and
CFO        

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ANNEX 1

SCHEDULE 2

                  Bank

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  Commitment Amount

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  Commitment Percentage

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Fleet National Bank
One Federal Street
Boston, MA 02109
  $ 30,00,000       60 %
KeyBank National Association
  $ 20,000,000       40 %
TOTAL
  $ 50,000,000       100 %

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