The modifications you can make depend on the type of user, as follows:
Built in administrator: You can change this username and password by logging in as the user, clicking the Username (upper right), selecting View Profile, clicking Edit, and making the changes.
Changing this affects
The name you enter to log in as the built-in administrator
The name that appears in the upper-right corner of the Port 8443 console
The name that appears in the administration console under Administrators
LDAP users (Direct administrators): User names and passwords are controlled in the LDAP source.
Internal TeamWorks users: User names cannot be changed; passwords can.
Administrators click the user in the Users list, click the Profile button, and enter a new password.
Internal users edit their profile to change their passwords.