Open the .vnmrc file in your favorite editor.
Change the entry that reads "initial_user_model_name=<what ever the initial user was>" with a new username.
Make sure the name you put in there doesn't currently have an user model.
Start the SpectroSERVER
Login to OneClick and use the new user. The password will be "spectrum".
Under the menu option "Control", there is a menu item called "Users", here you can add delete and modify users.