You can call and DL will sell an AF/KL fare to you. It will be issued on AF/KL stock (since there's no DL/JV segments) and thus requires an agent to know how to do that or get in touch with JV support desk.
The credit will be with AF/KL not DL in this case.
The ability for DL to directly ticket AF/KL fares (regardless of JV/DL segments) went away a couple years back. Basically AF/KL took back US sales from DL.