A notice to vacate is a formal declaration that someone is expected to leave a residence. A notice to vacate can be sent by a lessee, to indicate that he or she plans to leave by a set date, or it can be sent by a lessor, to indicate that a lessee is expected to leave by a certain date. A number of people use pre-printed legal forms to write out their notices to vacate, to ensure that they comply with the law, although a notice to vacate can also take the form of a simple written letter.