A two (2) weeks notice resignation letter is the most common letter used when notifying an employer of an official resignation. The best opening statement for a resignation letter is one that clearly states your intentions.Learn how to write a professional resignation letter with our step-by-step guide, easy to use templates and helpful tips. The signed 1945 resignation letter from Prime Minister Winston Churchill to King George, ending his ministry. Buy from the Raab Collection. Should you send a copy of your letter of resignation explaining why you're leaving to Head Office too?