<PAGE>   1
                                                                    EXHIBIT 10.4

===============================================================================





                                AMENDMENT NO. 1


                                       TO


                          MASTER ASSIGNMENT AGREEMENT


                                     AMONG


                         CHASTAIN CAPITAL CORPORATION,


                      MERRILL LYNCH MORTGAGE CAPITAL INC.


                                      AND


                      MERRILL LYNCH CAPITAL SERVICES, INC.





                          DATED AS OF OCTOBER 23, 1998






===============================================================================


<PAGE>   2






         THIS AMENDMENT No. 1 (the "Amendment") is made as of the 23rd day of
October, 1998 by and among CHASTAIN CAPITAL CORPORATION (the "Assignor") and
MERRILL LYNCH MORTGAGE CAPITAL INC. ("MLMCI") and MERRILL LYNCH CAPITAL
SERVICES, INC. ("MLCS"). By executing this Amendment, the Assignor, MLMCI and
MLCS agree to be bound by the terms of the Agreement as amended hereby.

                                   WITNESSETH

         WHEREAS, the parties entered into a Master Assignment Agreement, dated
as of August 21, 1998 (the "Agreement"); and

         WHEREAS, Assignor, by virtue of having breached its covenant set forth
in Section 9(i) of the Agreement, is in Default under the Agreement, and MLMCI
and MLCS have advised Assignor that an Event of Default has occurred and such
Event of Default is continuing;

         WHEREAS, Assignor has requested that MLMCI and MLCS refrain from
exercising their remedies with respect to the aforementioned Event of Default
until 5:00 p.m., New York City time on November 13, 1998 (the period from the
date of such Default until such time on November 13, 1998, being herein
referred to as the "Forbearance Period");

         WHEREAS, Assignor has entered into certain transactions that are
governed by that ISDA Master Agreement, dated as of July 10, 1998, between MLCS
and Assignor that are not contemplated in the Agreement and Assignor now
desires to grant to MLMCI and MLCS a right of cross-collateralization and
set-off with respect to such transactions in consideration of the forbearance
contemplated by this Amendment;

         WHEREAS, in order to effectuate the foregoing, the parties desire to
amend the Agreement in the manner provided herein;

         NOW, THEREFORE, in consideration of the foregoing and of the covenants
and agreements hereinafter set forth and of other good and valuable
consideration (the receipt and sufficiency of which is hereby acknowledged),
Assignor, MLMCI and MLCS agree as follows:


         SECTION 1.  DEFINITIONS

         (a) Capitalized terms used herein and not otherwise defined shall have
the meanings assigned in the Agreement. Capitalized terms used in the Agreement
whose definitions are modified in this Amendment shall, for all purposes of the
Agreement, be deemed to have such modified definitions.

         (b) The following defined terms are added:

                  "August 25, 1998 Swap Transaction" shall mean the transaction
         under the Swap Agreement entered into pursuant to a confirmation dated
         August 25, 1998, as the same may be amended, supplemented or otherwise
         modified from time to time.

                  "Forbearance Period" shall have the meaning set forth in the
         third WHEREAS clause of this Amendment.


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<PAGE>   3

                  "July 13, 1998 Swap Transaction" shall mean the transaction
         under the Swap Agreement entered into pursuant to a confirmation dated
         July 13, 1998, as the same may be amended, supplemented or otherwise
         modified from time to time.

                  "July 14, 1998 Swap Transaction" shall mean the transaction
         under the Swap Agreement entered into pursuant to a confirmation dated
         July 14, 1998, as the same may be amended, supplemented or otherwise
         modified from time to time.

                  "September 14, 1998 Swap Transaction" shall mean the
         transaction under the Swap Agreement entered into pursuant to a
         confirmation dated September 14, 1998, as the same may be amended,
         supplemented or otherwise modified from time to time.

                  "Subordinated Loan Agreement" shall mean the $40,000,000
         Subordinated Loan Agreement, dated as of November 13, 1998 between
         Assignor and Lend Lease Investment Holdings, Inc.

         (c) The definitions of the following terms are hereby amended and
restated as follows (and the parties confirm that all references to such terms
in the Agreement shall be to such terms as so amended and restated):

                  "Book Net Worth" shall mean the sum of (i) the equity of
         Assignor determined in accordance with GAAP and (ii) [such
         subordinated debt as related to the Subordinated Loan Agreement].

                  "Market Value" shall mean, for any Eligible Asset and for any
         transaction under the Swap Agreement, the value thereof determined by
         MLMCI (or its affiliate) from time to time (and at such times in its
         sole discretion) in the good faith exercise of its reasonable business
         judgement.

                  "Swap Agreement" shall mean that certain ISDA Master
         Agreement dated as of July 10, 1998 between MLCS and Assignor,
         including all amendments and supplements thereto and confirmations
         thereunder, including, without limitation, the September 14, 1998 Swap
         Transaction, the August 25, 1998 Swap Transaction, the July 13, 1998
         Swap Transaction and the July 14, 1998 Swap Transaction, as any of the
         foregoing may be amended, supplemented or otherwise modified from time
         to time.

         SECTION 2. THE NOTE; FINANCING STATEMENTS

         (a) The Note, attached hereto as Exhibit A, and all obligations of
Assignor thereunder is ratified and confirmed and all references to the
Agreement therein shall be deemed to mean the Agreement as amended hereby.

         (b) The parties confirm that all references to the Agreement and the
defined terms used therein in any financing statement of record that names
either MLMCI or MLCS as the secured party and Assignor as the debtor shall be
deemed to be the Agreement as amended hereby. 


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<PAGE>   4

         SECTION 3. MARGIN DETERMINATIONS


         Section 5(b) of the Agreement is amended by deleting the phrase "Swap
Agreement" in clause (2) thereof and substituting the phrase "September 14,
1998 Swap Transaction" therefor.

         SECTION 4. FORBEARANCE; COVENANTS

         (a) Assignor is in Default with respect to the Book Net Worth covenant
set forth in Section 9(i) of the Agreement, MLMCI and MLCS have advised
Assignor of such Event of Default and such Event of Default is continuing.
MLMCI and MLCS agree to refrain from exercising their remedies with respect to
such Event of Default during the Forbearance Period so long as Assignor
maintains a Book Net Worth of $50,000,000 and no other Default exists under the
Agreement.

         (b) Assignor hereby covenants and agrees to maintain a minimum Book
Net Worth during the Forbearance Period of $50,000,000; to maintain a minimum
Book Net Worth from period commencing immediately after the Forbearance Period
and ending January 31, 1999 of $65,000,000. 

         (c) Assignor hereby covenants and agrees to maintain a cash position
on its balance sheet of a minimum amount of $10,000,000; such cash position to
be free and clear of any lien, encumbrance or pledge.

         (d) Assignor hereby covenants and agrees to send MLMCI and MLCS, no
later than 5:00 p.m. November 13, 1998, $5,000,000 in immediately available
funds pursuant to the wiring instructions set forth on Exhibit B hereto, of
which MLMCI and MLCS shall apply the amounts as set forth on Exhibit B in
partial satisfaction of the aggregate Repurchase Price under the Agreement and
in partial satisfaction of the obligations of the Assignor under the Swap
Agreements. 

         (e) Assignor hereby covenants and agrees (i) to enter into the
$40,000,000 Subordinated Loan Agreement, pursuant to which the obligations of
Assignor to MLMCI and MLCS shall be senior to the obligations of Assignor under
the Subordinated Loan Agreement; (ii) to maintain such Subordinated Loan
Agreement; (iii) to notify MLMCI and MLCS of any borrowings under such
Subordinated Loan Agreement; and (iv) that Assignor shall not amend, modify or
otherwise supplement the Subordinated Debt Agreement in any manner that could
reasonably be expected to have a material adverse effect on the Agreement, the
Collateral or the Assignor. 

         (f) Assignor hereby covenants and agrees, with respect to the July 13,
1998 Swap Transaction that either (i) such Swap Transaction shall be unwound
before the close business on January 31, 1999 or (ii) MLCS and Assignor shall
have entered into an amendment to the July 13, 1998 Swap Transaction with
amended mark-to-market provision and such other conditions satisfactory to
MLCS, in its sole discretion. 

         (g) The forbearance granted hereby does not extend to any other
Default or Event of Default that has occurred or may occur at any time in the
future (including, without limitation, any event of default that occurs during
the Forbearance Period). MLMCI and MLCS hereby 


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<PAGE>   5

advise Assignor that, other than expressly provided herein, neither MLMCI nor
MLCS waives any Default or Event of Default which may exist, and that the
current non-exercise of rights, remedies, powers and privileges by MLMCI and
MLCS under the Loan Documents and applicable law with respect to such Defaults
or Events of Defaults, if any, shall not be, and shall not be construed as, a
waiver thereof, and MLMCI and MLCS reserve their rights (i) fully to invoke any
and all such rights, remedies, powers and privileges under the Loan Documents
and applicable law at any time any of them deems appropriate in such respect of
any Defaults or Events of Default that may exist, (ii) to refuse to make
available any further extensions of credit except in strict accordance with the
terms of the Loan Documents and (iii) to require that all Loans bear interest
at the rates specified in the Agreement. Nothing in this Amendment, and no
extension of credit made by MLMCI or MLCS on or after the date hereof, shall be
construed as an acknowledgment or determination by either MLMCI or MLCS that no
Default or Event of Default has occurred or is continuing.

         SECTION 5. TERMINATION OF AGREEMENT AND SWAP AGREEMENT

         Notwithstanding Section 13(g) of the Agreement, the definition of
Maturity Date or any other provision of the Agreement to the contrary, the
Agreement as amended hereby shall terminate when the Obligations thereunder
have been paid in full pursuant to the terms of the Agreement as so amended
(which terms shall include the due date and any other terms set forth in any
Confirmation Statement relating to a Loan); provided, that, so long as no Event
of Default shall have occurred, MLMCI and MLCS hereby covenant that any Loans
outstanding as of the date hereof shall be extended pursuant to the terms of
the Agreement through January 31, 1999. Such termination shall not require the
written request of Assignor.

         SECTION 6. NO REQUIREMENT TO LEND; NO FURTHER LOANS

         The parties confirm that all Loans under the Agreement are at the sole
and exclusive option of MLMCI and MLMCI is not now, and has never been, under
any obligation to make any Loan (including future Loans) under the Agreement.

         The parties hereby acknowledge that there shall be no further Loans
under the Agreement.

         SECTION 7. EXPENSES

         The expenses of the parties in connection with this Amendment
(including, without limitation, the fees and expenses of counsel incurred in
connection with the preparation of this Amendment) shall be paid by Assignor.


         SECTION 8. GOVERNING LAW; SEVERABILITY

         This Amendment shall be governed by and construed in accordance with
the laws of the State of New York applicable to agreements made and entirely
performed therein. Each provision of this Amendment shall be interpreted in
such manner as to be effective and valid under applicable law, but if any
provision of this Amendment shall be prohibited by or be invalid under such
law, such provision shall be ineffective to the extent of such prohibition or
invalidity, 


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<PAGE>   6

without invalidating the remainder of such provision or the remaining
provisions of this Amendment.


         SECTION 9. INTERPRETATION

         The provisions of the Agreement shall be read so as to give effect to
the provisions of this Amendment.


         SECTION 10. COUNTERPARTS

         This Amendment may be executed in any number of counterparts, each of
which counterparts shall be deemed to be an original, and all such counterparts
shall constitute but one and the same instrument.


         SECTION 11. RATIFICATION AND CONFIRMATION

         As amended by this Amendment, the Agreement is hereby in all respects
ratified and confirmed, and the Agreement as amended by this Amendment shall be
read, taken and construed as one and the same instrument.




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<PAGE>   7



         IN WITNESS WHEREOF, the parties hereto have executed this Amendment as
of the date first above written.

                                           CHASTAIN CAPITAL CORPORATION
                     
                                           By: /s/ StevenGrubenhoff
                     
                                           Name: Steven Grubenhoff
                     
                                           Title: CFO
                     
                     
                                           MERRILL LYNCH MORTGAGE CAPITAL INC.
                     
                                           By:  /s/ James B. Cason
                     
                                           Name:  James B. Cason
                     
                                           Title:  Vice President
                     
                     
                                           MERRILL LYNCH CAPITAL SERVICES, INC.
                     
                                           By:  /s/ John Mulholland
                     
                                           Name:  John Mulholland
                     
                                           Title:  Vice President





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<PAGE>   8

                                                                      EXHIBIT A




THIS NOTE IS NOT A
NEGOTIABLE INSTRUMENT.

NO TRANSFER OR SALE OF THIS NOTE SHALL BE MADE UNLESS SUCH TRANSFER IS EXEMPT
FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT OF 1933, AS AMENDED,
AND ANY APPLICABLE STATE SECURITIES LAWS OR IS MADE IN ACCORDANCE WITH SAID ACT
AND LAWS.



                                      NOTE


$35,000,000                    New York, New York               August 21, 1998

         FOR VALUE RECEIVED, CHASTAIN CAPITAL CORPORATION (the "Assignor")
promises to pay to MERRILL LYNCH MORTGAGE CAPITAL INC. (the "Payee") the
principal sum of Thirty-Five Million Dollars ($35,000,000) (or so much thereof
as shall have been advanced here against and shall be outstanding), in lawful
money of the United States of America, in immediately available funds, with
interest on each principal sum advanced here against or the unpaid balance
thereof with such frequency and to such location as is specified in the related
confirmation statement (in each case, the "Confirmation Statement") for such
advance (or on such other day and with such other frequency and to such other
location as may be mutually agreed upon by Assignor and the Payee) at said
office and in said money and funds from the date of the related advance until
January 31, 1999 (the "Maturity Date") at the rate per annum (based on a year
of 360 days and actual days elapsed) indicated on the related Confirmation
Statement attached hereto, but in no event higher than the maximum rate
permitted by law, and after such Maturity Date, or upon acceleration as
hereinafter provided, until said balances shall be paid, at the rate per annum
(based on a year of 360 days and actual days elapsed) equal to the greater of
(i) two hundred (200) basis points in excess of the interest rate for such
advance and (ii) two hundred (200) basis points in excess of the prime rate for
short term bank commercial loans as published in The Wall Street Journal,
changing as such published rate changes, but in no event higher than the
maximum rate permitted by law.

         Advances here against shall be in minimum amounts of $1,000,000 and
integral multiples of $100,000 in excess thereof. Assignor may request
disbursement of amounts borrowed hereunder upon not less than two (2) Business
Days' written notice to the Payee. The Payee is not obligated to make any
advances hereunder. The Payee is hereby authorized by Assignor to endorse on
the Loan Schedule amounts advanced here against, the rate of interest relating
thereto 


                                      A-1
<PAGE>   9

and any principal prepayments hereunder (as permitted by the Assignment
defined below), it being understood, however, that failure to make any such
endorsement shall not affect the obligations of Assignor hereunder in respect
of the amounts advanced here against.

         This Note is the Note referred to in the Master Assignment Agreement
(as amended, supplemented or otherwise modified from time to time, the "Master
Assignment Agreement"), dated as of August 21, 1998, between Assignor, Merrill
Lynch Capital Services, Inc. and the Payee, granting to the Payee a first
priority perfected security interest in the Collateral, as described therein.
The holder is entitled to the benefits of the Master Assignment Agreement and
may enforce the agreements of Assignor contained therein and exercise the
remedies provided for thereby or otherwise available in respect thereof. All
capitalized terms used in this Note and not otherwise defined shall have the
respective meanings set forth in the Master Assignment Agreement except where
the context clearly indicates otherwise.

         This Note and all other present and future obligations of any and all
kinds of Assignor in favor of the holder hereof, whether created directly or
acquired by assignment, whether absolute or contingent, shall, unless the
holder shall otherwise elect, forthwith be due and payable without notice or
demand of any kind (except as expressly provided in the Master Assignment
Agreement), all of which are expressly waived upon the occurrence of an Event
of Default.

         Assignor hereby agrees that any legal action or proceeding against it
for enforcement of this Note or of any judgment with respect to this Note may
be brought in the courts of the State of New York or of the United States of
America located in the City and State of New York, Borough of Manhattan, as the
holder may elect, and Assignor hereby irrevocably submits to the jurisdiction
of each of said courts, and waives any objection on the grounds of venue, forum
non conveniens or similar ground. Assignor irrevocably consents that service of
process in any such action or proceeding may be made upon Assignor by the
mailing thereof by the holder by United States registered or certified mail,
postage prepaid, to Assignor at the address set forth herein below the
signature of Assignor, and Assignor hereby further agrees that service of
process in such manner shall be full and sufficient notice of any such action
or proceeding.

         Assignor waives diligence, presentment of any instrument, protest and
notice of non-payment or protest and any and all other notices and demands
whatsoever in connection with the delivery, acceptance, performance, default or
enforcement of this Note. Assignor will pay on demand all costs of collection
(including reasonable attorneys' fees) paid or incurred by the holder in
enforcing this Note on default. As used herein, the word "holder" shall mean
the Payee or any endorsee of this Note who is in possession hereof, if this
Note is at the time payable to the bearer.




                                      A-2
<PAGE>   10



         This Note shall be governed by and construed in accordance with the
laws of the State of New York applicable to agreements made and entirely
performed therein, without regard to the conflict of laws principles thereof.

                                   CHASTAIN CAPITAL CORPORATION
           
                                   By: /s/ StevenGrubenhoff
           
                                   Name: StevenGrubenhoff
           
                                   Title:  CFO
           
                                   Address:  3424 Peachtree Road, N.E. Suite 800
                                             Atlanta, Georgia 30326
                                             Attention:   Steve Grubenhoff



                                      A-3
<PAGE>   11



                                 LOAN SCHEDULE


This Note evidences Loans made by the Payee to Assignor and the repayment of
principal by Assignor to the Payee, in the principal amounts and on the dates
and with the related interest rates set forth below as well as the total amount
advanced here against as of each such date:


<TABLE>
<CAPTION>

  DATE        PRINCIPAL        INTEREST         PRINCIPAL          TOTAL
            AMOUNT LOANED        RATE         AMOUNT REPAID     OUTSTANDING

<S>        <C>                <C>            <C>                <C>

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

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

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

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

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

--------   --------------     ----------     --------------     -------------
</TABLE>



                                      A-4
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                                                                      EXHIBIT B

                        WIRING INSTRUCTIONS AND AMOUNTS



To Merrill Lynch Mortgage Capital Inc.

         $________________

         Bankers Trust NYC
         ABA #:  021 001 033
         ACCT #: 008 129 14
         FAO: MLMCI Matched


To Merrill Lynch Capital Services, Inc.

         $________________

         Bankers Trust Company
         ABA#: 021 001 033
         ACCT #: 00 811 874
         Ref:  Merrill Lynch Capital Services, Inc., U.S. Dollar Swap Account



                                      B-1