A meaningful retirement letter needs to be professional, polite, and friendly in tone. This article will address how to write a retirement letter of resignation and provide an example that you can use as a template for your own retirement letter.A resignation letter should be written at least 30 days prior to the effective date of resignation. In the opening paragraph, make it clear that you are retiring. Use a retirement resignation letter template to inform your employer that you plan to leave the workforce. No reason was cited.