AT&T will cancel your Sprint account. When you go to change make sure you have your Sprint account number with you.
DO NOT cancel your Sprint account before the number is ported. If you do, your number is NO LONGER PORTABLE. You will lose your number. Account MUST BE ACTIVE to port the number from one provider to another.
This is a user to user forum. I am a user, just like almost everyone else on the site.
*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.