How to write a resignation letter that's effective immediately? How to Write an Immediate Letter of Resignation (4 steps).All that is required is one sentence. Pick the perfect wording and convey the message best suited for your situation. I am resigning my position effective immediately. Learn how to write a professional resignation letter due to unfair treatment. Use a one week notice letter template to inform your current employer that you plan to resign within seven days. Use this resignation letter example to advise your employer that you are resigning because of a scheduling conflict with another position. (For example, "I regret to inform you that I will be resigning from my position, effective immediately. Please accept this letter as my formal resignation.