I purchased a 4s that was through sprint, how can I unlock it to verizon?
Ask Sprint to unlock it. Even if they do, you may find that it's not usable with another US carrier.
You will be unable to get your phone on Verizon for 2 reasons:
1) Sprint will only unlock the GSM portion of its phones for INTERNATIONAL carriers
2) Verizon does NOT let you bring a phone to their service. You must purchase a Verizon phone.
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