I found some cheaper fares on UA's Hong Kong site and was wondering if anyone have had any probelms booking and upgrading fares from other UA sites. I would book a trip from ORD-HKG (use SWU to C) and then a separate HKG-SGN (use miles to u/g to F). The D class fare that comes up is not listed in UA's NA computer (called and asked), and is half of what cheapest C class fare.