Default [Q] Stop the new update? Maxx

Hey all, I have a stock Maxx non developer edition
Looks like I am getting the new update. The problem is I plan to go to T-Mobile.
Was at work today and the update box popped up. I hit late and set it for 1am. But I hit auto start.
Can I stop this from happening?
I'd like to take this phone to T-Mobile but have heard you can't call or text post update.