exchange numbers between two phones?

[DrEvel1]

I have two phones on my ATT account (one is used by my partner) - an iPhone3g (mine) and an iPhone 4 (his). I would like to exchange the numbers between the two phones, such that I get the iPhone4 and he has the 3G (he hardly uses his).. I would think this could be accomplished by simply exchanging the SIM cards between the two instruments, but I'm sure there is more to it than that (plus I can't get into an iPhone to do anything anyway). I would appreciate any guidance that you all can give me as to how this apparently simple process might actually be accomplished.

Thanks!

     JD

[Max69 ACE - Wizard]

The easiest thing to do would be to go to an AT&T store and have two new SIM cards configured. The iPone 3G uses a full size SIM, and the 4 uses the newer micro SIM, so it's a little more involved than just swapping the SIMs. There may be a small charge for the new SIM cards, but usually not.

[youngjm ACE - Professor]

There should not be a charge for the new SIMS.

[sandblaster]

Yes, it is as simple as swapping sim's but as the two previous posters have pointed out, that is not quite as simple with your iphones because they use different size sims. You could use the existing sims and swap  them by a) cut the iphone 3g full size sim down to micro-sim size and b) use a sim adapator to fit the iphone 4 micro-sim into the 3g iphone, but the best alternative is to get new sims as the previous posters suggest.