This is a trigger that commands an immediate protection switchover specifically on a named subcard controlled by this card, moving control from the active subcard to its standby. Unlike cardToRedundant's delayed, scheduled switchover, this one is immediate, so an admin uses it for an urgent, deliberate failover of a specific subcard component right now rather than a planned maintenance-window switch, accepting the instant traffic disruption that comes with it. For example, an admin triggers cardSubcardToRedundant on a subcard showing clear signs of an imminent failure, forcing an immediate switch to its standby before the primary fails outright and causes a less controlled outage.