I think there are two ways to change the username of a user:
-
Ask the user to do it themselves: They can go to their profile (
/user-settings/user-profile
), enter a new username there and press Save. -
Use the (Django) admin interface: Go to
/admin/users/user/
and sign in using a superuser (= staff) account (probably the one you created during setup of the instance). You can then select the user you want to change the username of, change it, and press Save.