To remove a Manager's role and login credentials, visit the Account Panel and select the Users tab. Select the user you want to remove, then click the Remove button to remove the Manager.
What happens when I remove a Manager?
When a Manager is removed from their role as Manager, they revert to an ordinary Employee and will be assigned to the default group. Their employee information remains intact. The Manager will not receive any notification that they were removed. The Manager's old group is automatically assigned to the Account Owner, but can be reassigned to a new Manager.
How do I remove a Manager that has left the Company?
First remove the role of Manager. They will revert to an ordinary employee. Then make them an inactive employee by visiting their employee record. For more information on removing employees, read this article.