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                                                                  EXHIBIT 10.04
                   MUTUAL ESTOPPEL AND MODIFICATION AGREEMENT


         THIS MUTUAL ESTOPPEL AND MODIFICATION AGREEMENT is made as of this 15th
day of June, 1999, by and among PNC BANK, NATIONAL ASSOCIATION (successor by
merger to Provident National Bank) (the "Bank"), THE PRUDENTIAL INSURANCE
COMPANY OF AMERICA ("Prudential") and EQK REALTY INVESTORS I ("EQK").

                                    RECITALS

         WHEREAS, the Bank, Prudential and EQK entered into a certain
Subordination and Intercreditor Agreement dated as of December 16, 1992 (the
"Intercreditor Agreement"); and

         WHEREAS, pursuant to the terms of a certain Mutual Estoppel and
Modification Agreement (the "Modification"), the parties set forth certain
agreements concerning the Intercreditor Agreement; and

         WHEREAS, the parties wish to make certain statements and agreements
regarding the Modification, the Intercreditor Agreement and the loans governed
thereunder.

         NOW, THEREFORE, for good and valuable consideration, the adequacy and
receipt of which are hereby acknowledged, the parties hereto, intending to be
legally bound, agree as follows:

         1.       All capitalized terms not defined herein shall have the
meanings given such terms in the Intercreditor Agreement.

         2.       The Bank hereby certifies as follows:


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                  (a)      The outstanding principal amount of the New
Provident Note, as amended and restated by the Sixth Amended and Restated Note
(the "PNC Restated Note") dated as of June 15, 1999 (collectively, the "PNC
Note") is $1,571,528.19;

                  (b)      The rate of interest under the PNC Note is either
three hundred and fifty basis points (3.5%) above the Euro-Rate (as such term
is defined in the First Amendment to Second Amended and Restated Loan Agreement
dated as of December 15, 1995 (the "PNC First Amendment") between EQK and the
Bank) or 1-1/8% above the Prime Rate (as such term is defined in the PNC First
Amendment);

                  (c)      There are no scheduled monthly payments of principal
required under the PNC Note; and

                  (d)      To the best of PNC's knowledge, there exist no
defaults under the PNC Note and the Subordinate Loan Documents, nor do any
circumstances exist which with the passage of time, or the giving of notice, or
both, would constitute a default under the PNC Note or the other Subordinate
Loan Documents.

         3.       Prudential hereby certifies as follows:

                  (a)      The outstanding principal amount under the New
Prudential Note, as amended by the Note, Mortgage and Loan Modification
Agreement dated as of December 15, 1995 and further amended by a First Amended
Note, Mortgage and Loan Modification Agreement dated as of December 15, 1996,
and as amended by a Second Amended Note, Mortgage and Loan Modification
Agreement dated as of December 15, 1997 (the "Prudential Modification
Agreement") between Prudential and EQK (collectively, the "Prudential Note") is
$43,794,149.14;


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                  (b)      The rate of interest under the Prudential Note is
8.88% per annum;

                  (c)      The monthly payment of interest required to be paid
under the Prudential Note is $324,076.70;

                  (d)      the maturity date (or the date on which the entire
outstanding principal balance plus all accrued interest thereon and any other
changes due and owing shall become due and payable) of the Prudential Note is
December 15, 1999; and

                  (e)      To the best of Prudential's knowledge, there exist no
defaults under the Prudential Note and the other Senior Loan Documents, nor do
any circumstances exist which with the passage of time, or the giving of
notice, or both, would constitute a default under the Prudential Note or the
other Senior Loan Documents.

         4.       Borrower hereby certifies that the statements made by the
Bank and Prudential in paragraphs 2 and 3 above, respectively are true and
correct and that there exist no defaults under any of the Subordinate Loan
Documents or Senior Loan Documents nor do any circumstances exist which with
the passage of time, or the giving of notice, or both, would constitute a
default under any of the Subordinate Loan Documents or the Senior Loan
Documents.

         5.       Bank confirms to and agrees with Prudential and Borrower as
follows: (a) that the Subordinate Loan Documents, including the amendments and
modifications hereinabove and that certain Fifth Amendment to Second Amended
and Restated Loan Agreement dated as of June 15, 1999 (the "PNC Fifth
Amendment"), remain subordinate to the Senior Loan Documents, including the
amendments and modifications thereto referred to hereinabove; (b) calculation
of the Contract


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Amount referred to in Section 4(b)(i)(A) of the Intercreditor Agreement shall
be based on the interest rate set forth in the PNC Note; (c) the Prudential Pay
Rate referred to in Section 4(b)(i)(B) of the Intercreditor Agreement shall be
the interest rate set forth in the Prudential Note (e.g. 8.88% per annum); (d)
notwithstanding the fact that the Contract Amount may be less than the Cap
Amount, EQK is permitted and EQK hereby agrees to make debt service payments to
the Bank in an amount equal to, but not exceeding, the Cap Amount; and (e)
paragraph 4(b)(i)(B) of the Intercreditor Agreement shall be modified by
deleting the un-numbered paragraph in the middle of page five commencing with
the phrase "Whenever the Contract Amount..." and ending with the phrase
"...interest at the Contract Rate" and substituting the following therefore:
"If the Contract Amount exceeds the Cap Amount at any time, the amount by which
the Contract Amount exceeds the Cap Amount shall accrue (and, if applicable,
shall be added to any previous excess) (but shall not be payable currently) and
shall represent a supplemental loan fee to Bank (the "Supplemental Loan Fee").
The Supplemental Loan Fee shall bear interest at the stated rate of interest
under the New Provident Note (the "Contract Rate") and shall be payable, along
with all accrued and unpaid interest thereon, on the maturity date of the New
Provident Note. In addition to and not in limitation of the foregoing, to the
extent any debt service permitted to be payable to Provident exceeds the amount
available for payment on the New Provident Note under the Cash Management
Agreement of even date herewith among EQK, Prudential and Provident (the "Cash
Management Agreement") or is not otherwise paid by EQK from operating reserves
or other sources, such excess shall not be payable currently, but shall accrue
and shall be added to the principal of the New Provident Note and shall bear
interest at the Contract Rate.


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         6.       The parties hereby agree and confirm (a) that all references
to any or all of the Senior Loan Documents or Subordinate Loan Documents
contained in the Intercreditor Agreement shall mean the Senior Loan Documents
as amended by the Prudential Modification Agreement and the Subordinate Loan
Documents as amended by the PNC Fifth Amendment and the PNC Restated Note; (b)
all of the terms and conditions of the Intercreditor Agreement shall be
extended until all sums under the Senior Loan Documents have been paid in full;
and (c) that all of the terms and conditions of the Intercreditor Agreement
remain in full force and effect and binding upon the parties hereto and their
respective successors and assigns.

         7.       This Agreement may be executed in any number of counterparts
which, taken together, shall constitute one and the same instrument.

         8.       This Agreement shall be governed by and construed in
accordance with the laws of the Commonwealth of Pennsylvania.




                     [SIGNATURES ARE ON THE FOLLOWING PAGE]


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         IN WITNESS WHEREOF, the parties have executed this Mutual Estoppel
Agreement as of this 15th day of June, 1999.

                                               PNC BANK, NATIONAL ASSOCIATION

                                               By:  /s/ Andrew D. Coler
                                                    ---------------------------

                                               Title: Vice President
                                                      -------------------------


                                               THE PRUDENTIAL INSURANCE COMPANY
                                               OF AMERICA

                                               By:  /s/ David Graham
                                                    ---------------------------

                                               Title: Vice President
                                                      -------------------------

                                               EQK REALTY INVESTORS I

                                               By:  /s/ Don Henry
                                                    ---------------------------

                                               Title: VP
                                                      -------------------------


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