I bought an Economy (O) fare for a one-way Brisbane to Sydney in January for a flight in July. Excessively early but hey! It cost me A$114.99. The fare is now A$116.

Background info over. Why can't I change my booking online? The flight is QF559. I bought it on Qantas.com. It isn't with jetstar and it is an e-ticket. There's no 'change your flight' button next to the OLCI (greyed out) button.

Has it been 'ticketed' (another online FAQ answer for not being able to change the ticket?

thanks in anticipation of your replies.