Mortgage Modification. You may be able to reach an agreement with your lender to modify the terms of the mortgage loan.The mortgage modification agreement is a legal document between a lender and borrower to change an existing loan's terms. A loan modification is a procedure which allows you to either permanently or temporarily change the terms of your lending agreement. Final Mortgage Modification Agreement. If the parties agree to a final or long- term mortgage modification, the Debtor or the Creditor shall file a Motion to. Struggling to pay your mortgage? Learn how the Flex Modification program works, as well as other options for changing your loan terms. A modification occurs when the mortgage servicer adjusts a borrower's interest rate, length of the loan, or principle balance. Mortgage. To begin the process of modifying your mortgage loan, reach out to your lender and explain your situation.