I recently picked up a thunderbolt from a friend. I'm currently using an iphone but about to make the switch. I googled if I could switch my service online instead of going into the store and it says I can. My question is if I switch my number to the thunderbolt online, is that all I have to do? Is there any special thing you have to do to have 4G working beside filling out the transfer form online? It has the 4G sim card in the phone