I am flying to Sydney on an award ticket ( J class). I want to stay at least three days in HKG ( instead of 1 night) so I called AAdvantage to make the changes. Unfortunetly, they do not have J for the dates that I am looking for, but the agent offered me coach. I am a handicapped person, and I am worried that downgrading to coach will make my trip a nightmare. Since my original seat was on J, If I downgrade, will CX give me a J seat in the case they have any empty seats? or Should I go to the airport the day before to see if they give me a seat? What options do I have if any....

Just in case, here is a copy of my itinerary

4 MAY CX 883 LAX HKG
6 MAY CX 111 HKG SYD
18 MAY CX 110 SYD HKG
19 MAY CX 880 HKG LAX

Any suggestions will be greatly appreciated. Thank you guys