Hi. I am flying LHR-SFO on Tuesday. I have an economy saver award ticket. There looks to be business saver award availability on the earlier flight because the earlier flight appears to be Polarized. Mine, sadly, has not been. Do you think United would allow me to switch to the earlier flight and then upgrade? If so, is there still a chance that the plane may go back to a non-Polarized version? If so, I am less inclined to switch because I could end up in a middle seat. Plus, I really only like to spend cash or miles on the true Polaris seats. Thanks!