Unfortunately, it is somewhat of a hassle beyond that. They can confirm the upgrade (or waitlist) that way. But before your flight segment, they need to go to the airport or a United ticketing office to sign a blue authorization form. The only exception to this is if you and the other person have the same last name. This may or may not be a big deal depending on how far they're located from an airport (not sure if subcontracted stations can handle this sort of thing--you may want to confirm the details with UA first) and how soon your ORD-HKG leg on UA is.