Droping a flight segment from itinerery.
My folks have cashed in some of their QF points on a trip from Oz to Europe that involves Cathay, BA and Qantas. The Cathay part of the trip is over (good seats in Y, average food). Next is BA out to Athens, then back to London later this year and onwards to Tokyo before QF home Oz.
On the return to London leg, they can't stay more than 1 night/24 hours as they are having the stop over on this leg. If they decide to come back early on their own steam, how would this affect the remainder of trip? Would they need to tell BA or QF? I believe if you don't show for a leg on multi segment trip they may cancel the remainder of the flights. They're not worried about getting any mileage back on the cancelled flight segment.
Any help appreciated.