You can cancel your refundable Qantas ticket within 24 hours of booking for a full refund, or check options for non-refundable fares—call Qantas at +61 7 5230 3273 (Australia) or +1 888 859 9010 (USA) for quick help!
For non-refundable fares, cancellations might come with fees, so be sure to review your ticket’s terms to understand the rules for your booking.