If you both agree, the amendment must be recorded in writing, either by drafting a new written document outlining the terms of the lease, or by amending the existing written lease. A rental agreement, also known as a housing rental agreement, short-term rental agreement or insured short-term rental agreement, is a contract that defines the obligations and expectations of the relationship between a landlord and a tenant during the lease. There are obligations that you and your landlord have, which may not be stipulated in the contract, but which are prescribed by law and are implicit in all rental agreements. These conditions are part of the contract, even if they have not been expressly agreed between you and your landlord.