In the body of the letter, state your intended retirement date (your last day) and your thoughts on a transition plan. Remember that a retirement letter is a formal one, which may also go in your employee file.So, be sure to make it as straightforward and formal as possible. Pima and Santa Cruz counties join City, U.S. Fish and Wildlife Service to establish Santa Cruz River. Representatives signing the MOU. To ensure that every citizen can have complete confidence in the integrity of the Federal.