Originally Posted by Confus

They will only cancel if you have two bookings on the same flight. Same day is fine.

Originally Posted by bisonrav

You usually get checked into the final destination in the US, but being checked in for DUB isn't a problem particularly as long as you don't use the BP in the transit route at Heathrow. Either use the NCE BP if you have it or go landside and back in with it. You'll then miss conformance on the DUB flight and be offloaded. Assumes no checked bags.

Originally Posted by KARFA

that's fine. obviously don't check in for the LHR-DUB flight.