Originally Posted by
bawm
For others reading, please note that this is completely incorrect. Each segment on a PNR can be ticketed separately (and even plated on different carriers). This wouldn't apply if you bought from ac.com of course.
bawm
+1. This is the truth.
For a booking like this that was done through a TA, it is best to deal with the TA for rebooking, or at least an experienced AC reservations/ticketing agent. For AC to do any rebooking, they need to at least 'take' the SQ SFO-HKG coupon, and if they do not have control of the coupon, they need to work this out with SQ first.