Reimbursement report for those that already had a bit of their reimbursement used. I already had $40 used on Delta, I couldn't remember for the life of me what it was. called Amex July 30, told them I wanna change to United agent said it could be a problem because some of the credit was used, but said no problem, changed it to United. I waited 2 days just in case Aug 1 I bought $200 in Mileagebank credit, used it that day to book a $360 flight. Aug 4 $160 credit posted for remaining amount of the $200 credit.
This is a cool hack, though really most years I just use it on Delta to fly my pet ATL MEX. I can also report that taxes on award tickets usually posts on Delta as reimbursement from my experience, but perhaps thats changed.