Actually yes you can, you just have to cut it, you can google how to do it, and then you have to re-program the phone to have the 3G work again (at least that what I had to do, the VPN wasn't configured but it only took some copy paste and it worked and I don't know anything about programming) you can google that too.
And of course it has to be unlocked and activated if you're going to use it on another carrier.