It looks like baclubflyer might already be in the air, but I was searching to post a question on almost the same flight. My return flight PVG-DTW has one open seat. I've been checking for weeks to try to get in an exit row or economy comfort, but it just keeps getting fuller.
My flight leaves at 10am. There is another flight that leaves at 9:35am going through NRT which has better seats on offer.
Is it possible to volunteer for another flight before you get to the airport? I'd do it with no compensation other than more leg room ...