Looked into breaking apart the flights....the 777 flight would clear with an upgrade applied, however will the upgrade confirm on BNA-ORD-NRT, and then waitlist for NRT-BKK? Or will the entire itin waitlist based on seats for NRT-BKK. Turns out the NRT-BKK flight is the one holding up the upgrade.....therefore is it holding up ORD-NRT because of the same flight number, or do all flights going 1 direction need to upgrade at the same time?