Loosing the remaining reservation after HKG should be no problem if I understand your situation correctly.
If you have checked luggage your best bet most likely is trying to check the luggage only to HKG (with a good reason, like meeting somebody there whom you need to give something from your luggage - if you have enough time in HKG for that). Then recheck there to your new flight.
So far I have been successful in short checking luggage with a good reason.