Send Later
Find, edit or cancel an email before it goes out.
An email you've scheduled to send later sits under Send Later until its time comes, and you can still change your mind about it.

Select Send Later in the sidebar. It only appears while at least one email is waiting to go out.
Select the email to open it in the composer.
Edit it, change its send time, or select Cancel send to move it back to Drafts, unsent.