How to Write an Immediate Letter of Resignation (4 steps). How to write a resignation letter that's effective immediately?It's time to quit the job, and you're not giving two weeks' notice. Here's how to politely write a resignation letter, effective immediately. Use a one week notice letter template to inform your current employer that you plan to resign within seven days. In the first sentence, clearly state your intention to resign and that your resignation is effective immediately. The purpose of this message is to inform you that I am resigning my position at EvilCorp. Our advice on how to write a resignation email effective immediately is to keep it short and to the point which is what we've done.