Upgrading an AT&T phone online -- how does the transition occur?

[deckeda]

Thanks everyone. Seems it's all for naught in this case. My dad was wanting to take advantage of the $100 5S promo online, but the site is partially broken and when it was suggested he call Customer Care, they told him the only option was to pay the regular $200 and they'd credit him $100 on his bill, which he declined due to the overall stupidity of the situation.

He just signed up with PureTalk and will keep his old iPhone 4 for now, and AT&T will lose about $60/month of revenue.