Here's my situation. I am a QF Plat and have a QF flexible business class booking for MEL-SYD.
The ticket is on a non-QF(OW) stock with ongoing flights after a stopover in SYD.
I would like to switch to an earlier (30 Min. flight) since that would be an A330.
QF told me "Go to your travel agent".
TA told me "We would need to do a full reissue/new issue" (which I can't/don't do for a specific reason)
If I get to the airport early enough would QF CI change my flight to the earlier one, or is that a "mission impossible".