We've rounded up tips and examples for writing a resignation letter that'll help you maintain work relationships long after leaving a company. Below is a sample union resignation letter.You should check your union's constitution and bylaws to see if it is specific to whom a resignation must be sent. Sample 2: Acceptance of Resignation with Immediate Effect. I am writing to formally acknowledge receipt of your resignation letter dated October 10, 2051. In the body of the letter, state your intended retirement date (your last day) and your thoughts on a transition plan. Employers may also want to consider the impact an immediate separation would have on remaining employees. After the meeting, provide the formal written notice to the manager via email or letter. Here is a sample template to craft a resignation email:.