By including a per diem amount in the letter, the parties will not have to execute another payoff letter if the termination date. To get a payoff letter, ask your mortgage lender for an official payoff statement and let them know what the projected closing date is.You must request a mortgage payoff letter from your lender. Please accept this as my authorization to issue a payoff statement to. Through an effective date of . The letter must also state the amount due, per diem interest and the date the Payoff Letter will expire. What is a Payoff Agreement? A payoff agreement is an informal contract in which a creditor agrees to accept the balance of a debt owed as full payment. A payoff letter shows the remaining balance on your mortgage, including fees, interest, etc. Learn more about what a payoff quote is and how to request one.