When a person leaves the company, off-board that person directly from Teams.
Go to Teams > Team Organization.
From the Employees tab, select the checkbox of the person you want to offboard.
Click Actions > Offboard Employee.
Follow from step 4 of End coverage for an employee.
Note
Once you complete the off-board employee process, the user card will display with an expiration date when their access to Fullcast will end.