Assumption of Loan Requirement Letter for disaster loan servicing action request packages. About this document and download.What Is Required to Assume an SBA 504 Loan? An assumption transaction may be accomplished with or without consent of the lender. The transaction involves only a title transfer. An assumable mortgage involves one borrower taking over, or assuming, another borrower's existing home loan. Find out how it works. When you assume a mortgage from a home seller, you become responsible for that loan at its existing interest rate and terms. What information do I need to provide during this process? Complete the assumption agreement: Fill out and sign the loan assumption agreement, which legally transfers the mortgage responsibility to you.