I believe the licenses will remain. You need to replace the install license with one with less features. Did you keep a copy of the activation key prior to installing the current license? If so, re-apply that one.
You other option may be to contact firstname.lastname@example.org with a copy of your sh ver and ask for a license key with the bare minimum feature set.
You can aleo run clear configure all to remove all configurations. The firewall leaves basic settings as if it was facory reset.
License keys remain