Hi Team, I looking for clarification on a cancelled connection flight claim. The trip was the return segment booked SFO-AMS on BA in World Traveler Plus on a single PNR for my partner and son.

The flights were BA284 SFO-LHR which had an on time departure and early arrival to LHR, and BA438 LHR-AMS which was eventually cancelled after being delayed.

They were offered a replacement flight LHR-AMS the next day which wasn't going to work so cancelled the ticket and requested a refund for the non-flown LHR-AMS segment.

What compensation would be expected in this scenario?

Thanks in advance!