Thanks Award Nexus!
Just found availability on CX in F from HKG-ORD visible for use with AA miles which is vastly preferable to the HKG-NRT-ORD I had booked. I certainly wouldn't have called in to check availability as often as I've been able to keep track doing occasional searches. Plus, it's nice to see the inventory decrement by one after making the change.
Pleasure to hear that you found an F seat.
Have a good flight!