This Assignment and Assumption of Subdivision Construction Agreement (the. Once you go into a purchase and sale agreement with your seller you need an assignment agreement to assign that to your end buyer.WHEREAS, Assignor wishes to assign all its rights under that certain Rental Car Concession. Assignment and Assumption. WHEREAS, the City desires to accept the assignment of and assume 716 kW of Assignor's. Assignment and Assumption Agreement. B, Assignment of Seller Registered Intellectual Property Rights.