To change your username:
- Open your profile by clicking on your profile picture.
- Once on your profile page, click on the pencil icon.
- Change your username and click on the "save changes" button.
- Your username can only be changed once! If you want to change it again, select the "Buy a name change" button. It could be purchased for gems.
Please note that you don't need to change the name immediately after the change name purchase.