If employee left your company, you can set him as not active and issue his license to a new employee. Here are the steps to follow:
Step1: On the Dashboard, tap on users.
Step2: Click on that user you want to cancel. You may select
the user based on User ID or Full name.
Step3: Click on “active” to make him not active
Step4: Scroll further down and Tick on “do not assign
license” so the license to make the license free to use for someone else
Step5: Click save to deactivate the user and deactivate
his or her license.