https://knowt.com/note/5c89a433-c25f-4214-a615-e7c67961324a/Can-I-cancel-the-economy-flight-with-Luf

https://knowt.com/note/5c89a433-c25f-4214-a615-e7c67961324a/Can-I-cancel-the-economy-flight-with-Luf