Qantas allows passengers to cancel their flight without penalty if done more than 24 hours before scheduled departure. Qantas 24 hour cancellation policy gives passengers flexibility to change plans up until the day before. To cancel your Qantas flight or have questions related to Qantas 24 Hour Cancellation, you can visit the Airlines Pet Policy. Additionally, you can contact at 800-227-4500 or +1-844-902-4930 (OTA Skip-Waiting).