Originally Posted by
Jazzop
You may want to add that international upgrades on DL must be processed >24 hours prior to departure. One cannot carry PMUs in one's wallet on the hope that an empty seat in J will open up on the day of departure. I don't know how this applies to the NW world, however.
If this hasn't changed already, it is changing in the near future. Among all of the discussion about the 2010 program, it was announced that PMUs can be used on the day of departure. Don't remember the specifics about dates, as this is not something I would be overly inclined to do.