If you want to cancel a flight go to the booking, which you would like to cancel.
You will find your booking by clicking on "Booking and tickets" and then you select the journey by clicking on "Order details".
You can either select one part of the trip or request a refund for the whole trip:
After clicking on "Request Refund of entire trip" this window will open up:
Here you can decide if you want to cancel or rebook your flight(s).
If you want to rebook the flight this window will open:
Please enter all the relevant data, so we can let you know if rebooking is possible and how much it will cost.
After all you click on "complete cancellation" and the request will be sent to your support team, which will take care of your request.