One of our employees is currently on a Verizon "family plan" and we want to give him an extra iPhone 5 we have at our office and get him using it but staying on his own plan. Trouble is, our iPhones are all on AT&T and when he went to get the AT&T iPhone 5 activated Verizon told him "the phone was not compatible" with Verizon? Is this true? Can it be done somehow?