In brief: The following article will outline how to deactivate a user. Deactivating a user will deny them access to the EzTix administrative panel.
Login to EzTix
Select the Global Event Management Tab on the right hand side of the menu.
Select the User Management tab on the left hand side of the screen.
You'll then see a list of your current active users. On the right hand side of the user you would like to delete - select "Deactivate User"