Refunds against enplaned or checked-in flights

Users will no longer be able to refund amounts that correspond to a passenger who is enplaned (BORD) or checked-in (CKIN) on flights. If a passenger is checked in or enplaned on a flight, and the cost of their journey needs to be refunded, simply reverse their check-in (passenger not in BORD or CKIN status) to refund the amounts.