Edit, sign, and share assumption agreement online. No need to install software, just go to DocHub, and sign up instantly and for free.1. Read the agreement carefully to understand the obligations. • Fannie Mae form Assumption and Release Agreement (form 6625, 6626, 6627, or 6628);. An assignment and assumption of lease is a legal real estate document that allows one party to transfer rights and obligations of a lease to another party. Taxes and Supporting Documents tabs.