They'll probably still need A+ blood the week after you move, or a couple of weeks after? Can you schedule an appointment in advance so you don't forget to make the donation even if you don't do it right now?

Definitely understand it's a difficult calculus! In the UK blood banks usually get a really good response to urgent calls and end up with more blood than they can use, and prefer donors who commit to a regular schedule and give even when there isn't a particular reason. So if it's anything like that where you are, the September 23^rd donation may do a lot of good, as it will fall during the inevitable dip in donations that follows an urgent drive.

A blood bank isn't a person with emotional needs who needs to be reassured that you understand the urgency. They have practical needs, which are often best served by people who are able to be realy rational and pragmatic about donation. If you have a means of contacting them, you may be able to ask whether, given you can't manage August 26, Sep 8 or Sep 23 is better for them. Good luck, though! I know it feels really awful to skip giving blood when you in theory could do so.

Awesome, well done!