How to Write an Immediate Letter of Resignation (4 steps). How to write a resignation letter that's effective immediately?Use a one week notice letter template to inform your current employer that you plan to resign within seven days. Pick the perfect wording and convey the message best suited for your situation. In this article, we cover everything you need to know about writing a resignation letter without notice and provide an example to get you started. The purpose of this message is to inform you that I am resigning my position at EvilCorp.