Originally Posted by
irishguy28
Delta is not a Flying Blue airline, so upgrading a Delta flight using Flying Blue miles may mean that you have to go through the separate Skyteam Mileage Upgrade Program, which has very different rules. Only full-fare Y on DL can be upgraded via this mechanism, according to the Skyteam website:
I think what you are alluding to is to upgrade non-codeshare flights - for example, if I want to fly on DL metal within the US on a flight with no KL flight number, then only a full fare Y ticket can be upgraded. As I understand it, the flights I want to upgrade are on DL metal but are KL codeshare (KL6012/6005 respectively). Certainly the reward booking tool shows that I can spend miles on a pure redemption on these flights. However, if anyone knows any different please shout before I ping KLM and spend an hour on the phone....