As others have said, you have to factory restore your device in order to start over. I can't speak for Jailbreaking because I don't jailbreak my devices.
Some of the advice here doesn't work. You can't just delete the app and remove it from game center because once you re-install the game, it will still bring back your old game. This is because it's within your system file that appears to be saved in the ipad. Jailbroken device may have something that allows you to delete the files completely.
When you do a factory restore, Do NOT restore from back up as it will bring up your old game, so you have to set it up as a new device. This is the only option. Yes it is annoying, as some of you don't want to lose everything. But if you want to start over, then you have to sacrifice one thing or the other.
However, there is a way to get the new account and then get your back up so you don't lose other important stuff:
- Back up your device.
- Factory restore and select "Set up as New"
- Install Clash of clans
- You have to create a new game center account.
- open CoC
- Finish the tutorials.
- Once the tutorials is finished and you created a in-game name, then perform another factory reset and this time "Restore from backup"
- Once your restoration is complete, immediately go to game center and log out of your old one and log in with the new game center you just created.
- Open CoC and it will detect that your new game.
- Read the direction carefully and type "CONFIRM" Viola, you now have a new account and not lose your back up.