Due to unpredictable circumstances I may have to change onward plans when I arrive at HKG on a one-way LAX-HKG-SIN award ticket.

I may have to stay on in HKG and abandon HKG-SIN leg, or buy a seat to another destination. It's a long story...

Obviously I could just fail to board the HKG-SIN leg, but I'd rather do the right thing and let Cathay know I won't be flying.

Would there be any problem with that?