Greetings,

Your Game Center and device can only support one saved-game at a time. So if you’d like to start fresh, you’ll have to give your device a factory reset. 

Please use these instructions with caution; factory resets remove all personal data on your device. Supercell cannot be held responsible for any loss of data.

To safely restart your device and minimize chances of losing data, I recommend following Apple’s official steps (you will need a computer and iTunes)::

1) Sync all device content to your computer: GUIDE
2) Import all of your important pictures and videos: GUIDE