Tried searching on this topic but no luck. I'm flying NW in a couple of weeks in V on the way out and T on the way home. I'd like to use my Delta FF number on the way out when I'll get full MQMs, then switch to use my Alaska FF number on the way home to get the last two segments I need to requalify for MVP. I'm concerned that if I change to the Alaska number before points for the first flight have posted to Delta, I'll end up getting everything credited to Alaska instead. This wouldn't be the end of the world, but I'm trying to maximize the value I get from the trip. Has anyone done this before and gotten credit on different programs for different legs from the same itinerary?