Last year when CX re-timed the SUB flights from mid afternoon till early hours of the next morning due to volcanic activity in the area which gave me something like an 18 hour layover, CX put me up in the Regal Airport hotel.

The change was known in advance and I called CX to see if they would provide a hotel as the schedule had changed from when I booked and would not have booked the revised schedule. They told me to check on departure at AMS. When I got to check in on the day of the flight, the agent saw a note in my booking and told me to go to the ticket desk to collect a hotel voucher for HKG. Happy with the outcome but didn't know if they were going to provide it until I checked in at the desk.

S