Taking Sprint S4 to Verizon? Other Carriers? topic

Greetings, I can't seem to find a definite answer or guide to this. I have a sprint galaxy s4 and once my contract was up I was looking to get off sprint and onto another contract, looking at verizon as my friends happen with them. I know they both use cdma. If I have them unlock the phone, can it be brought over and used that easily? If not, what must I do? Custom root? Find a verizon s4 motherboard with clean esn? I'm willing to do it to not spend a few hundred bucks on a new phone. I'd liketo give it to my mother and get the s6 for myself when it comes out.