HI Guys, I am a newbie for this site. I have iPad 2 which I got it from Vodafone as a 24 month contract with vodafone network (included microsim) , now I want to change the sim to O2 network (new micro sim with different network) , do I need to unlock iPad prior to change the sim? without unlocking the iPad 2 can I able to change the sim? is it will work? Please let me know kindly. because existing network(Vodafone) not good as I expected. please let me know.