For players to be able to modify their Clash of Clans username, they must have attained Town Hall Level 5.
Although the game enables you to change your username for free the first time, subsequent name changes incur a fee.
Remember that diamonds are necessary for every name change beyond the initial one.
In addition, players must wait at least seven days before seeking to alter their names again.
Steps to alter your Clash of Clans username:
1. Advance to Town Hall Level 5 (if not already achieved).
2.Click the Settings icon in the lower-right corner of the display.
3. Select Additional Options from the Settings Menu.
4. Select Change Name from the list of available options.
5.Click Continue only if you wish to utilise the free name change service once.
6. Continue to follow the prompts.