Disabling a user account
Step 1: Navigate to Administration/Users in the left menu
Step 2: Click the Actions button for the user you want to disable
Step 3: Select Edit in the dropdown menu
Step 4: Toggle the Active button off, and click save. The user will now be locked out of the system, and unable to log in.
Toggling the Active button will not immediately throw users out of an ongoing session. They will not be able to log in the next time they start a session.