How to write a resignation letter that's effective immediately? I need to prioritize my health, so I am resigning immediately." Expression of gratitude. Formal notification of resignation. Specify the last day of work. Bro just hand a basic resignation letter in and tell your direct line manager what you think of him. They don't care neither should you. Please accept this as my. While it might be tempting to gush, settle scores, or otherwise write something informal, the best resignation letters stick to the script. However, sometimes, that's not an option, as some circumstances call for an immediate resignation.