You can use this resignation letter sample as a base to write a letter with your own name, dates, and other information. Are you looking for a professional and formal resignation letter with a 1month notice period?Formal Resign Letter Template. I hope to stay in touch. A simple resignation letter format includes a resignation statement, an appropriate notice period, and an expression of gratitude. You may request a CEO Determination within 90 days of the date of the notice of the Benefit Determination.