I'm sorry I was unclear about that part. These tickets are booked using cash and not miles. So as of now I have my KLM/AF Flying Blue frequent flyer number associated with these bookings. However, I have managed to acquire VN Lotusmiles Gold status as well.
Can I still keep my flying blue account on these bookings to earn flying blue miles while leveraging my VN status for the free check in bag or will I have to change the frequent flyer number on these bookings to my VN one to get those benefits?