How to write a resignation letter that's effective immediately? Start with the facts and be direct.My resignation is effective immediately. (For example, "I regret to inform you that I will be resigning from my position, effective immediately. How to write resignation letter with immediate effect word format. I regret to inform you that I must resign with immediate effect from my position as head data analyst at Microsoft. This would be to establish tech training schools like Per Scholas, which includes a Chicago branch. A resignation letter must include a statement that you are leaving your employment and the date on which your resignation comes into effect.