I'm thinking of upgrading my S4 to an S7 and it looks like the S7 uses a different type of SIM card, so I should be getting a new one with the phone. How does this work with my existing phone and SIM card? Will it stop working? Do I need to do something to stop it so it won't be like I have two lines on my account? I'm new to SIM stuff so I don't know how to move from my current one to a new one. Thanks!