I am in the UK, part way through a westbound AONE3 booked last February with some dummy dates and am now trying to rebook the remaining sectors. I want to use CX on JFK/YVR and also CX on SFO/HKG. However the booking engine says no flights are availabe between YVR and SFO, even if I try routing via SEA or LAX.

Any bright ideas please?