Originally Posted by
NOLAnwGOLD
Just give Delta your NW FF number. Make sure that when you get your boarding pass, the NW number is on there. Sometimes you have to make sure the Delta number isn't there....
If you have already flown, then you have to send in your BP and receipt to NW for credit.
Except if the BPs had another FF# on them except for your NW WP#, because you can't get miles on two ST/partner airlines. In that case, you'd probably have to get DL to straighten this out if they credited them to DL/another ST FFP.
Also, if travel was on a ticket sold by NW, you can try calling WP first, you might not have to send them in. I've had NW coded, QX operated flights where a phone call was all that was necessary to get credit.