Rooting is the process of allowing users of smartphones, tablets and other devices running the Android mobile operating system to attain privileged control (known as root access). In simple word by rooting your android operating system you can change almost anything. He ask to change gameloop id because if his emulator gets detected when he was cheating he will get ban again again . Even if he is not using any cheat. So changing the Android ID will solve the problem. You can't normally change your android id without rooting . For more info about rooting search on youtube and google