A resignation letter should be written at least 30 days prior to the effective date of resignation. In this article, we'll guide you through the essentials of writing a resignation letter when going back to school, ensuring you leave on good terms.You are free to resign with thirty days notice. Check with the union and don't count on what I'm saying but the rule is give thirty days notice. The purpose of this Administrative Instruction is to establish and clarify procedures regarding. The employee shall fill out the necessary absence forms upon their return. Fill out the form on this page to get a free editable Google Docs template with sample teacher resignation letters to help you compose your own. After Vice President Megan Sweet's resignation last month, the deadline is Dec. 6 to submit an application to finish her term. After Vice President Megan Sweet's resignation last month, the deadline is Dec.