I realize you are booked through QF, so your situation is a little different from mine and you have a open jaw connection which complicates things. But, for what its worth (if anything), I am in the same boat with a JL ticket. I called JL this morning and they refused to change my flight to depart from another U.S. city (I suggested DFW or ORD) at a time closer to my original booking. They were very adamant about "no changes allowed." They were willing to put me on the other JFK flight to HND, but there were no seats available in first class. Oh well, I'll survive.