Is it possible to change a CDMA phone from another carrier over to cellular south?

Hi everyone. I want to know if I purchase a CDMA phone that was used with another carrier but it is unlocked is there any way I would be able to program it for Cellular South. I contacted Cellular South about it and they said they were unable to do it. I just wanted to know if there is anything I can do myself as far as doing a flash or reinstalling software onto the phone.|||it is possible, but very complicated and not all phones work, you should contact Cellular South and ask them what they can do... you really don't need to contact your previous service provider.