How to write a resignation letter that's effective immediately? Learn how to write an immediate resignation letter with our comprehensive guide, including tips, examples, and a customizable template.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. I am writing to announce my resignation, effective in 24 hours. Learn how to write a professional resignation letter with our step-by-step guide and easy to use templates.