This mortgage assumption agreement allows a new borrower ("Borrower") to assume an existing mortgage from the original borrower. 1. Read the agreement carefully to understand the obligations.A mortgage assumption is the process of a buyer taking over, or assuming, the seller's existing home mortgage. Get to grips with assumption agreements. This simple guide explains their purpose, key elements, and how they affect your business dealings. Your easy guide for completing Mississippi Assumption Agreement of Deed of Trust and Release of Original Mortgagors stress-free. Form edit decoration. 9.5. 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.