For example, if we have a flight with a code
SU0102, does it always goes from Sheremetyevo to John F. Kennedy or the origin and destination points can change for this flight? The same about schedule: does a flight
SU0102 always leave at 15:40 and arrives at 17:10 or the hours can change?
In short words, can the schedule, origin and destination change for a flight with a certain number and if so is it frequent?