Document:

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                                                                   EXHIBIT 10.99

                               THIRD AMENDMENT TO
                              AMENDED AND RESTATED
                          CREDIT AND SECURITY AGREEMENT

     THIS THIRD AMENDMENT TO AMENDED AND RESTATED CREDIT AND SECURITY AGREEMENT
(this "Amendment") is made and entered into effective as of March 11, 1999
between CRESCENT REAL ESTATE EQUITIES LIMITED PARTNERSHIP, a Delaware limited
partnership (the "Lender"), and CRESCENT OPERATING, INC., a Delaware corporation
(the "Borrower").

                                R E C I T A L S:

     A. The parties executed that certain Amended and Restated Credit and
Security Agreement dated as of May 21, 1997, as amended by that certain First
Amendment to Amended and Restated Credit and Security Agreement dated as of
August 11, 1998 and by that certain Second Amendment to Amended and Restated
Credit and Security Agreement dated as of September 21, 1998 (collectively, the
"Original Agreement"). All capitalized terms not otherwise defined in this
Amendment will have the same meaning as described in the Original Agreement.

     B. The Borrower has requested that the Lender make a loan to it in the
principal amount of $19,500,000, the proceeds of which are to be used to
accomplish the acquisition of various assets associated with the cold storage
business through a joint venture entity to be established and funded together
with Vornado Operating Company (the "Americold Loan").

     C. In order to induce the Lender to make the Americold Loan, the Borrower
has agreed to modify the Original Agreement to cross default and cross
collateralize the Loan with the Americold Loan.

     D. The Borrower is willing to modify the Original Agreement for such
purpose on the terms and conditions set forth herein.

     In consideration of the mutual covenants set forth herein, and for other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree as follows:

     1. Section 1.1. The following definitions are hereby added to Section 1.1
of the Original Agreement to read as follows:

          "Americold Credit Agreement" means the Credit and Security Agreement
     dated as of March 11, 1999 between the Borrower and the Lender, as such
     agreement may be amended, supplemented or otherwise modified from time to
     time.

          "Americold Note" means the promissory note of the Borrower payable to
     the order of the Lender under the terms of the Americold Credit Agreement,
     as the same may be modified, supplemented, or amended from time to time,
     and any note or notes issued in substitution or replacement therefor or in
     addition thereto.

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     2. Section 1.1. The definition of "Secured Obligations" in Section 1.1 of
the Original Agreement is hereby amended in its entirety to read as follows:

          "Secured Obligations" means the collective reference to the unpaid
     principal of and interest on the Note, the Line of Credit Note, the COPI
     Note, the Americold Note, and all other obligations and liabilities of the
     Borrower to the Lender, whether direct or indirect, absolute or contingent,
     due or to become due, or now existing or hereafter incurred, which may
     arise under, out of, or connection with, this Agreement, the Line of Credit
     Credit Agreement, the COPI Credit Agreement, the Americold Credit
     Agreement, the Note, the Line of Credit Note, the COPI Note, the Americold
     Note, the Pledge Agreement, or any other document, made, delivered or given
     in connection therewith, in each case whether on account of principal,
     interest, reimbursement obligations, fees, indemnities, costs, expenses or
     otherwise.

     3. Section 4.1. Section 4.1 of the Original Agreement is hereby amended and
restated in its entirety to read as follows:

          As security for the prompt payment, performance, and observance in
     full of the Secured Obligations, the Borrower hereby pledges and assigns to
     the Lender, and grants to the Lender a continuing security interest in and
     lien on all of the following property now owned or at any time hereafter
     acquired by the Borrower or in which the Borrower now has or at any time in
     the future may acquire any right, title or interest (the "Collateral"):

          (i)    all Accounts;

          (ii)   all Chattel Paper;

          (iii)  all Documents;

          (iv)   all Equipment;

          (v)    all General Intangibles;

          (vi)   all Instruments;

          (vii)  all Inventory;

          (viii) all books and recordings pertaining to the Collateral; and

          (ix)   to the extent not otherwise included, all Proceeds and products
                 of any of the foregoing, in any form (whether cash or non-cash)
                 and all collateral security and guarantees given by any Person
                 with respect to any of the foregoing.

     4. Section 7.1. The word "or" is hereby deleted from the end of subsection
7.1(i) of the Original Agreement; the word "or" is hereby added to the end of
subsection 7.1(j) of the Original Agreement; and the following paragraph (k) is
hereby added to Section 7.1 of the Original Agreement to read as follows:

     (k) an "Event of Default" under the Americold Credit Agreement;

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     5. Section 8.11. Section 8.11 of the Original Agreement is hereby amended
and restated in its entirety to read as follows:

          The parties agree that the Lender shall have the right to apply the
     proceeds of any Collateral under this Agreement, the Line of Credit Credit
     Agreement, the COPI Credit Agreement, or the Americold Credit Agreement in
     its sole discretion, against the Secured Obligations under this Agreement,
     the Secured Obligations under the Line of Credit Credit Agreement, the
     Secured Obligations under the COPI Credit Agreement, or the Secured
     Obligations under the Americold Credit Agreement.

     6. Remainder of Original Agreement. Except as amended hereby, the Original
Agreement shall continue in full force and effect in the form that was effective
immediately before the execution of this Amendment.

     7. Counterparts. This Amendment may be executed in any number of
counterparts, all of which taken together shall constitute one and the same
document.

     8. Binding Effect. This Amendment shall be binding upon and inure to the
benefit of the respective successors and assigns of the parties hereto.

     9. Governing Law and Severability. This Amendment shall be governed by and
construed in accordance with the laws of the State of Texas. Whenever possible,
each provision hereof shall be interpreted in such manner as to be effective and
valid under applicable law.

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

                             CRESCENT OPERATING, INC.

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

                             CRESCENT REAL ESTATE EQUITIES
                             LIMITED PARTNERSHIP

                             By: Crescent Real Estate Equities, Ltd.,
                                 its general partner

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

                                       3<PAGE>   1
                                                                  EXHIBIT 10.100

                               THIRD AMENDMENT TO
                                 LINE OF CREDIT
                          CREDIT AND SECURITY AGREEMENT

     THIS THIRD AMENDMENT TO LINE OF CREDIT CREDIT AND SECURITY AGREEMENT (this
"Amendment") is made and entered into effective as of March 11, 1999 between
CRESCENT REAL ESTATE EQUITIES LIMITED PARTNERSHIP, a Delaware limited
partnership (the "Lender"), and CRESCENT OPERATING, INC., a Delaware corporation
(the "Borrower").

                                R E C I T A L S:

     A. The parties executed that certain Line of Credit Credit and Security
Agreement dated as of May 21, 1997, as amended by that certain First Amendment
to Line of Credit Credit and Security Agreement dated as of August 11, 1998 and
by that certain Second Amendment to Line of Credit Credit and Security Agreement
dated as of September 21, 1998 (collectively, the "Original Agreement"). All
capitalized terms not otherwise defined in this Amendment will have the same
meaning as described in the Original Agreement.

     B. The Borrower has requested that the Lender make a loan to it in the
principal amount of $19,500,000, the proceeds of which are to be used to
accomplish the acquisition of various assets associated with the cold storage
business through a joint venture entity to be established and funded together
with Vornado Operating Company (the "Americold Loan").

     C. In order to induce the Lender to make the Americold Loan, the Borrower
has agreed to modify the Original Agreement to cross default and cross
collateralize the Loan with the Americold Loan and to reduce the maximum
aggregate principal amount of the Loan to $17,200,000.

     D. The Borrower is willing to modify the Original Agreement for such
purpose on the terms and conditions set forth herein.

     In consideration of the mutual covenants set forth herein, and for other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree as follows:

     1. Section 1.1. The following definitions are hereby added to Section 1.1
of the Original Agreement to read as follows:

          "Americold Credit Agreement" means the Credit and Security Agreement
     dated as of March 11, 1999 between the Borrower and the Lender, as such
     agreement may be amended, supplemented or otherwise modified from time to
     time.

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     "Americold Note" means the promissory note of the Borrower payable to the
order of the Lender under the terms of the Americold Credit Agreement, as the
same may be modified, supplemented, or amended from time to time, and any note
or notes issued in substitution or replacement therefor or in addition thereto.

     2. Section 1.1. The definitions of "Note" and "Secured Obligations" in
Section 1.1 of the Original Agreement are hereby amended in their entirety to
read as follows:

          "Note" means the amended and restated promissory note of the Borrower
     payable to the order of the Lender under the terms of this Agreement, as
     the same may be modified, supplemented, or amended from time to time, and
     any note or notes issued in substitution or replacement therefor or in
     addition thereto, substantially in the form of Exhibit B hereto, in the
     maximum principal amount from time to time outstanding of up to Seventeen
     Million Two Hundred Thousand Dollars ($17,200,000), evidencing the
     obligation of the Borrower to repay the Loan, as modified, supplemented or
     amended from time to time.

          "Secured Obligations" means the collective reference to the unpaid
     principal of and interest on the Note, the Term Note, the COPI Note, the
     Americold Note, and all other obligations and liabilities of the Borrower
     to the Lender, whether direct or indirect, absolute or contingent, due or
     to become due, or now existing or hereafter incurred, which may arise
     under, out of, or connection with, this Agreement, the Term Loan Credit and
     Security Agreement, the COPI Credit Agreement, the Americold Credit
     Agreement, the Note, the Term Note, the COPI Note, the Americold Note, the
     Pledge Agreement, or any other document, made, delivered or given in
     connection therewith, in each case whether on account of principal,
     interest, reimbursement obligations, fees, indemnities, costs, expenses or
     otherwise.

     3. Section 2.1. Section 2.1(a) of the Original Agreement is hereby amended
by deleting the phrase "Thirty Million Four Hundred Thousand Dollars
($30,400,000)" and inserting the phrase "Seventeen Million Two Hundred Thousand
Dollars ($17,200,000)" in lieu thereof.

     4. Section 4.1. Section 4.1 of the Original Agreement is hereby amended and
restated in its entirety to read as follows:

          As security for the prompt payment, performance, and observance in
     full of the Secured Obligations, the Borrower hereby pledges and assigns to
     the Lender, and grants to the Lender a continuing security interest in and
     lien on all of the following property now owned or at any time hereafter
     acquired by the Borrower or in which the Borrower now has or at any time in
     the future may acquire any right, title or interest (the "Collateral"):

     i)    all Accounts;

     ii)   all Chattel Paper;

     iii)  all Documents;

                                      -2-
<PAGE>   3

     iv)   all Equipment;

     v)    all General Intangibles;

     vi)   all Instruments;

     vii)  all Inventory;

     viii) all books and recordings pertaining to the Collateral; and

     ix)   to the extent not otherwise included, all Proceeds and products of
           any of the foregoing, in any form (whether cash or non-cash) and all
           collateral security and guarantees given by any Person with respect
           to any of the foregoing.

     5. Section 7.1. The word "or" is hereby added to the end of subsection
7.1(j) of the Original Agreement, and the following paragraph (k) is hereby
added to Section 7.1 of the Original Agreement to read as follows:

          (k) an "Event of Default" under the Americold Credit Agreement;

     6. Section 8.11. Section 8.11 of the Original Agreement is hereby amended
and restated in its entirety to read as follows:

          The parties agree that the Lender shall have the right to apply the
     proceeds of any Collateral under this Agreement, the Term Loan Credit and
     Security Agreement, the COPI Credit Agreement, or the Americold Credit
     Agreement in its sole discretion, against the Secured Obligations under
     this Agreement, the Secured Obligations under the Term Loan Credit and
     Security Agreement, the Secured Obligations under the COPI Credit
     Agreement, or the Secured Obligations under the Americold Credit Agreement.

     7. Remainder of Original Agreement. Except as amended hereby, the Original
Agreement shall continue in full force and effect in the form that was effective
immediately before the execution of this Amendment.

     8. Counterparts. This Amendment may be executed in any number of
counterparts, all of which taken together shall constitute one and the same
document.

     9. Binding Effect. This Amendment shall be binding upon and inure to the
benefit of the respective successors and assigns of the parties hereto.

     10. Governing Law and Severability. This Amendment shall be governed by and
construed in accordance with the laws of the State of Texas. Whenever possible,
each provision hereof shall be interpreted in such manner as to be effective and
valid under applicable law.

                                      -3-
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     IN WITNESS WHEREOF, the parties below have executed this Amendment
effective as of the date first written above.

                                    CRESCENT OPERATING, INC.

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

                                    CRESCENT REAL ESTATE EQUITIES
                                    LIMITED PARTNERSHIP

                                    By:  Crescent Real Estate Equities, Ltd.,
                                         its general partner

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

                                      -4-

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