Assumption of Loan Requirement Letter for disaster loan servicing action request packages. About this document and download.A loan assumption is a lending process where a borrower formally takes over or "assumes" a current home loan from a home seller. An assumable mortgage involves one borrower taking over, or assuming, another borrower's existing home loan. Find out how it works. What Is Required to Assume an SBA 504 Loan? When you assume a mortgage from a home seller, you become responsible for that loan at its existing interest rate and terms. Anyone have any insight on Chase's assumption loan process. It's incredibly slow and requires faxing or mailing documents in. An assumable mortgage is a type of home loan that can be transferred to a new borrower.