You can automatically free up any licenses that haven't been synchronized in the last 90 days by marking this option in Resco Woodford's Administration Settings.
Select if you want the system to purge unused licenses after 90 days of inactivity. These licenses will become available again.
The exact behavior is: When all licenses are assigned, both Auto-assign licenses and Auto-free up unused licenses are enabled, there's at least one user that has not synchronized for at least 90 days, and a new user tries to synchronize; in this case, the license from the user that has not synchronized (in at least 90 days) is transferred to the new user trying to synchronize.