Originally Posted by
Andriyko
Airlines may just cancel seats in a particular cabin which will show up as a cancelation in the reservation system. The point is that the cabin is withdrawal/canceled. I don't see why passengers in other cabins should be notified if they are unaffected by the cancelation. Maybe they are but none of them comes here to tell us about it.
Other passengers would be notified if the flight number changed. This would typically require that the ticket be reissued.
Some systems notify passengers when there's a significant aircraft type change, although this usually isn't enough to give the customer a right to either rebook or cancel the ticket for free.