Click on "Manage rides" tab on the side menu to access all bookings you made for the 2-month transport pass/single trip bookings you made.
Click onto the individual trip that you wish to cancel, click "cancel" on the bottom and confirm your cancellation. Your trip has been successfully cancelled.
Please cancel your ride as soon as you know that you do not require the service so that the slots can be opened up to other passengers that require the service.
If you have really last minute changes, you will still be able to cancel right till before the trip starts.