Communicate with the Lender: Discuss the possibility of assumption with the existing mortgage lender early in the process. Keep in mind that the average loan assumption takes anywhere from 45-90 days to complete.A loan assumption agreement allows them to understand what is expected from them and ensures that they are aware of their rights and legal responsibilities. VA loan rules permit an otherwise eligible VA borrower to apply for a new VA mortgage loan in the wake of a prior VA loan assumption under certain conditions. Ensure all necessary financial information is accurately provided. Assumption of Loan Requirement Letter for disaster loan servicing action request packages. About this document and download.