I had American Express that issued the tickets call Emirates. They too were amazed at the lack of customer service or responsibility accepted for a downgrade. After the AMEX rep was transferred several times they were eventually told that I should ask for a voucher when I check-in for the flight, but couldn't provide any details about the voucher.

I did check to see if it was just a one day equipment change, but unfortunately it is a permanent change.

Thank you all for your input. I will let you know how the voucher plays out, if at all.