Failover simply means the phone switched from the Primary ICP to the Secondary ICP due to connectivity reasons... it lost contact with the Primary ICP and went into "failover" to the Secondary ICP. When it returned it will go into registration reason is "Forced" and it should do it on it's own when the Secondary Controller can reliably communicate with the Primary of the resilient pair. In a properly built clustered network environment this should not be service effecting to the user, except during the period that the phone actually switches controllers. To force a phone back, assuming the Primary Controller is operating properly, it can simply be rebooted or wait until the phone automatically switches back.
