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.In this article, we explain how to construct a formal resignation letter as well as provide an example to help you write your own. Your resignation letter should be upbeat and positive. It should be written to your immediate supervisor, expressing warm feelings for the company, and regrets. Here are some of the best resignation letter examples and templates you can use to leave your job under a variety of circumstances. Write the date first. Bid adieu to your existing job with professionalism. Use our resignation letter template. This is an example of a resignation letter for contractors and clients.