Compensation fo downgrade F-J
I had this situation on a HKG-SIN sector in February 2011 as part of an AA F award ticket. CX changed the equipment from 74A to regional 777 several months ahead of my travel date. I did not contest the downgrade with CX on the day as cash compensation appears to be offered only if downgraded at short notice.
I contacted AA after travel and subsequently received 4000 miles.