Hello, I have a LG G4 That is set up for Verizon. Is there a way to set up the phone to use any service or does a service have to chosen first? Also, can the sim card be used for other services or will I need to get a new sim card? I want to set up the phone for a service like Tracfone? Do I have to have a sim card? Can I get a blank sim card and program it myself?