You can change your name.

However, the first change is free, and subsequent changes will cost 100 coins. You can change to any username, but names containing inappropriate words cannot be used. Also, the name must be between 2 and 15 characters.

Follow these steps to change your name: 

• Tap the "icon image" at the top left of the home screen
• Tap "Edit"
• Tap the edit button next to the username