If you want to transfer your miles to US thats fine, however you would be using them on UA.BOS-ORD-PVG. Do your search on UA and then call US. Do your search ORD-PVG, if you find a flight then do a search for BOS-ORD.If you find flights then call US and see if they have them.(They should) The problem with Wood is they take time to transfer, maybe 10 days.