Not sure your circumstances but Id like to highlight something form Red Roo last year in last years DSC thread
http://www.australianfrequentflyer....e-status-credits-sc-75580-19.html#post1437863
So changes should be allowed. The rule dont appear to have changed since last year. The wording apears to be the same
If you reconstruct the sentence and break the and's & or's apart it becomes:
"If you change your initial qualifying booking and travel is completed outside the promotional period, this bonus offer will not apply."
"If you change your initial qualifying booking or travel is completed outside the promotional period, this bonus offer will not apply."
"If you cancel your initial qualifying booking and travel is completed outside the promotional period, this bonus offer will not apply."
"If you cancel your initial qualifying booking or travel is completed outside the promotional period, this bonus offer will not apply."
They all seem to read to be OK with changes. I think people are getting caught up with the first few words.
Anyway Red Roo's previous comment still stands and should be good enough to argue for the points if needed.
I personally have changed a booking but changed it to April this year so cant personally say how it went. But if needed i will use Red Roo's comments above.