So this is my first time DH in a middle seat. (forgive my ignorance)

I submitted my request for add pay on a recent DH flight and just received a request for a copy of my boarding pass. Is this a requirement? Not sure if I can go back and find a copy of my boarding pass; any ideas?

I followed the contract (5-C-1-J), which only states reservation number, seat occupied, and a description of the event. I attached an image of my pairing from CCS to the request. Is this not all the justification that is required?

Thanks for the input.