That is the effective date for many of FDA's legal powers.

那是FDA多项法律权利的生效日期。

Start with a formal salutation, such as " Dear [Supervisor's Name], " Statement of resignation: Clearly state your intention to resign from your position, including the effective date of your resignation.

开场白：以正式的称呼开始，例如“尊敬的[主管姓名]” 辞职声明：明确说明您辞去职务的意向， 包括您辞职的生效日期。