OK, I've been reading this for years but have never posted. Now I am stumped and don't know where to go for answers. We booked a flight from LHR to LAX via Continental in Business Class and tried to upgrade on miles. Continental said it was not possible as this was a code share flight operated by United. So, being a member of UA FF program as well, we tried to upgrade through them. Again, not possible because this is a code share flight. Is this all BS? Thanks.