As late as 14 april they offered to put me on a earlier & direct flight from ZRH to AMS instead of a later ZRH-CDG-AMS one. The earlier direct flight was a HV flight so i refused. This one was on a DL/006 issued ticket. However when booking i always ask the Delta agent for the AF/KLM PNR and depending on the operating carrier i use the native KLM and/or AF apps and websites once outside Delta territory.

To get one's point across when needed speaking dutch @AMS or german @ZRH certainly doesn't hurt either.