Originally Posted by tennisguru

Reserves do not have a trip guarantee. Nor is there such a thing as an IA with conflict for reserves. You'll get what you actually fly on your X day paid over reserve guarantee, and all the rest of the trip will pay towards whatever month's RES guarantee those days fall on. Trip credit pays towards whatever month the last day of the trip is on towards RES guarantee. You will get zero pay for the conflicting reserve assignment.