Is this an award or revenue ticket? If revenue, and assuming that PVG and XIY are both stopovers, IMO you should have UA ticket SFO-X/ICN-PVG-ARNK-XIY-X/ICN-SFO as an open jaw, and buy PVG-XIY separately on Elong (elong.com) or C-Trip (ctrip.com) as a domestic oneway. This should work out to be cheaper also.