Air China HAK PEK MUC FRA PEK HAK flights are business except HAK PEK HAK and I wanted to use evouchers to upgrade economy Y shorthaul HAK PEK HAK. However Air China has only first class on this sector or economy, can I use 2 evouchers to jump to first....No. Can I use miles to upgrade to first........No. My thought was upgrade should be to next available class of travel with evouchers or at least use miles, according to MM Shanghai I am wrong.