How to write a resignation letter that's effective immediately? Your resignation letter should be to the point, concise, and clear.Here are examples of resignation letters for different levels and professions, each tailored to a specific personal reason. This letter includes details such as your last day of employment, transition steps, words of gratitude and, optionally, your reasons for leaving. Former Clark employee Mary Jane Rein, in which she shared her account of events leading to her resignation on Sunday.