American connecting to Japan

What if I don't have the actual printed ticket for the third country on arrival? I want to reach Shanghai merely to drop off my Airmule bags. My original itinerary ends here, but I have an additional segment on a different airline and can show the purchase confirmation for my next flight out of China that's happening within 24h.

Will there be any problem getting the free transit without visa and accessing the non-sterile section in order to deliver my bags and check-in for my next flight?