Qantas allows eligible travelers to upgrade their seat to the premium class cabin if they have already booked a seat in its standard cabin. Moreover, the airlines provide several ways through which travelers can make an upgrade, which include classic upgrade awards and Domestic On Departure Upgrade Rewards. Furthermore, travelers can also use the Bid to Upgrade Qantas option, where they have to place a monetary bid to move into a higher cabin. To learn more details related to the upgrade, contact the customer service of Qantas or read the blog linked above.