Notify your department personnel office regarding your intention to retire. Find out when you should submit a letter of resignation.In the body of the letter, state your intended retirement date (your last day) and your thoughts on a transition plan. Retirement applications may be submitted up to 180 days (six months) before you terminate your teaching service. In the opening paragraph, make it clear that you are retiring. In the body of the letter, immediately state your intention to resign and provide your reasoning, including only positive feelings towards your work experience. Regardless, there are steps to be taken in preparing for and entering into retirement or resigning from your position. A retirement letter is a type of resignation letter, but the main difference is its purpose.