When conducting a failover of a Cisco NAC cluster, first determine the status of the node you’re currently on:

. /perfigo/common/bin/fostate.sh
My node is active, peer node is standby

Next, conduct the failover by doing one of the following commands:

shutdown
reboot
service perfigo stop

Source

http://www.cisco.com/c/en/us/td/docs/security/nac/appliance/configuration_guide/416/CAM/416cam_book/m_ha.html#wp1047066