If you have uploaded your track you can't make any changes. But don't despair, you just contact support and we'll help you out.
If you want to make changes in your profile (including artist name) you need to log out of the app and let the Amuse support know what the change is. We will help you out and email you back when it is done. Remember to always contact us regarding this kind of errands from the email used on the Amuse account so we can be sure about who is asking for the changes.