I am sorry to hear that you're considering leaving the Verizon family, Jill99. I understand the importance of being able to retain your mobile number. I can certainly go over some details. Is there a specific reason you're wanting to change carriers?
As for your phone, providing it was not purchased to be active on a prepaid account, the device is already unlocked, though we cannot guarantee that it will work on another carrier. The ability to port your number to another provider is not dependent on the device, rather the number itself. You will need to reach out to the other carrier prior to porting to see if they are able to bring your number over.