I’m flying MAN to EZE via AMS return business class. The return AMS to MAN aircraft has been changed to all economy plane, I’ve been instructed by KLM to pick up a voucher at AMS. As I don’t have much time between flights and I’m not sure where to go for the voucher or what it actually consists of, I’m not sure what to do about this involuntary downgrade (that section of the flight is only 1.20 hrs) any advice welcome.