Iphone 3GS with ATT family plan question

[Audi09]

Im trying to upgrade my 1 year old account to a Iphone 3GS. I have 2 phones each with a its own # on 1 family plan. My phone (blackberry) is 1 year old and the other one (lg shine) is 2+ years old. Im able to upgrade online for a 3GS for 200$ on the Lg Shine phone. Is it possible to do that upgrade online and when the phone comes in the mail can I put the sim card from the blackberry into the Iphone? Would it work?

 

[MacBacker]

I know you're eligible but I just went into the store for the upgrades to my family plan. I wouldn't know how that would work ordering through the internet as I believe all new iPhones come with new SIM cards.

Can you go to an Apple or AT&T store?

 

[Goodeye]

if you go into an ATT store they can help with that and will do it with no problems. They don't care which line is using the iPhone as long as they 1) get a contract renewal and 2) you pay on time.