If you upload your release and it is in the 'Ready' or 'Offline' status, you can still make changes. You can also update your release's metadata if it is in the 'Distributed' status.
Just click on 'Action' -> 'Edit Release Metadata'
To learn how to change your artist name, click here.
If it is in any other status, such as 'Waiting Approval' or, you won't be able to make changes as the release is already set for distribution or distributed.