I have a question regarding KLM codeshare flights booked on Delta.com. I am considering flying to Germany via Amsterdam on Delta, where I would switch to a KLM-operated flight. I have heard about issues concerning seat assignment when booking on Delta.com, that the seats for the KLM operated flight selected on Delta's website don't stick. Is this true, and what is the best way to book this sort of flight? Would I be better off booking everything on KLM's website, or would I be OK with using Delta's website to book?
Also, with this type of flight, since the second flight would be operated by KLM, is it possible to get both boarding passes upon checkin with Delta, or would I have to pick up the second one in Amsterdam. Also, upon checkin with KLM in Germany for the return, would I be able to pick up both boarding passes, or would I have to get the Delta boarding pass in Amsterdam?
Any advice you can provide surrounding this topic would be greatly appreciated.
Thank you very much.