I was waiting in-line to re-book flights after a delay and heard a term used from the agent at the next counter. The person said, "Try to re-route them on XXX flight and if that does not work, 'FIB' them". I may not have the correct spelling, but what does this term mean? Is it Full Involuntary Booking or something similar? Would this be used in connection with Rule 240???

Can anyone explain this? Thanks.