In the event that a user is no longer a member of your organization or for some other reason their job duties have changed, their user account can be disabled.
Navigate to Settings > Users or Settings > Network Users.
Search for and select the user whose account needs to be disabled.
Select the drop-down arrow on the far right of that user line.
Select Disable.
A confirmation message will appear.
Select OK to confirm disabling of this user.
A message will be displayed at the top of the screen verifying that the account has been disabled.
The user will now have been removed from the user list.
Disabled users may be viewed in the user list by selecting the gear to the right of User Usage and selecting Include Disabled.