Originally Posted by John_doe_

Thanks for reply.
Correct, it's the policy of China, but I booked Air Canada's ticket, it's Air Canada actually run the "remove" progress and as the carrier, so I wanted to ask whether there is a way can have contact for H&C reason for a seat and not to be removed.
e.g., if I booked Air China's ticket, I will ask "whether there is a way to contact in Air China to keep a seat for H&C reason".

If I ask the embassy, they may just tell me: we just make the general policy, but it's up to Airlines to determine which 40% passengers can be onboard. E.g. I heard that US airlines will sort from ticket price, but Air Canada is very random.