Thinking of taking on a mortgage from a family member? Then you'll likely look into a mortgage assumption agreement.Requirements – NJSA A. 1. A cover sheet (or electronic synopsis). Ensure all necessary financial information is accurately provided. Log in to your Freedom Mortgage account. THIS MORTGAGE ASSUMPTION AGREEMENT (hereinafter referred to as the. "Agreement") made and entered into as of this ______(1)______ day of ______(2). A mortgage assumption agreement is basically you coming in and saying sign this paperwork I'm still responsible for the mortgage.