I am flying HKG-CDG return early December. I hold an ipgrade certificate due to involontary downgrade from F to J earlier this year. It says that it can be used at time of check-in. Can I use it at OLCI and how (should it be entered in my ooking somewhere)? If I can only use at airport, can I make a special trip to the airport in the morning (the flight is late evening)? Would I have priority over upgrade with miles? Any practical tip would be useful. My certificate expires at the end of the year, so I must use it on this trip.