State your intention and resignation date. Use an attractive header with your personal contact info, include the recipient's name, company and address, and include the date.Write the date first. 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. Please accept this letter as a notice of my resignation. Learn how to write a professional resignation letter with our step-by-step guide, easy to use templates and helpful tips. I will go over a step-by-step resignation template letter you can use, how to structure it and provide examples of resignation letters. My resignation is effective immediately. Time frame: Clearly state your last planned day of employment.