take the phones to your provider and explain what you just said, they should be able to do just what you like pending the company you are with is
CDMA...which, if your over seas's is not likely.
In other words, if you have
CDMA phone, and want to use them over seas's, you are out of luck. Call Verizon, they may be able to help you, otherwise, the phones won't work....period!