To change your username, please write in to Customer Service with your current username and 3 username choices you wish to change it to. Please make sure any name you choose is within the Community Guidelines. If you select an inappropriate name, you may be asked to select a different one.
To change your Profile Name you contact The Customer Service at http://asksupport.custhelp.com/app/ask There you will be have to provide 3 profile names you would like to have if in case the one you want has been taken, I suggest you chose the profile name you want the most in the beginning because it is most likely to be selected. And please don't let it be inappropriate and make sure it follows the Community Guidelines :) Your welcome and have a wonderful day :D