Leaving a job isn't easy. How to write a resignation letter that's effective immediately?Learn how to write an immediate resignation letter with our comprehensive guide, including tips, examples, and a customizable template. Dear Sirs: Effective immediately, I am not a member of UFCW Local 99. A one (1) week notice letter is written notification provided to an employer that an employee will no longer be working with the company within seven (7) days. A simple resignation letter format includes a resignation statement, an appropriate notice period, and an expression of gratitude. (For example, "I regret to inform you that I will be resigning from my position, effective immediately. It's just another example of Fake News," he wrote in a post on Truth Social.