If you for some reason want to quit using failover and use the firewalls as standalone units, you must do things in the right order to release the team:
The Standby firewall must be taken away first. Do this by turning the power off, disconnect all cables or log on as admin via the serial cable and select 4. Leave failover team and become standalone.
Change type of the Active firewall on the Failover Settings page by pressing the Deactivate failover button.
If you want to replace a unit in the failover team, you must first split the team and then make a new one.