There must be one default user established at all times.
When you use the system for the first time, and until you establish a new user, the user named ‘Sample’ is the default. When you create a new user for the first time, using the ‘New User Initialization’ screen, that new user is automatically established as the default user. As new users are established, you use this screen if you want to change the ‘default’ user.
To avoid confusion and conflict, the system options and the system header captions can only be changed by the default user. This is because these options and captions apply to all users once they are set.
You change a user name by changing the value in the ‘User Name’ data field. A user name is limited to 36 characters
Note that you can only change a user name if you are signed in to the system as that user.