Signed-in users can also find this guide, with screenshots, under Help in the app.
You can push back the end time of a confirmed booking, or cancel it, from the Reservations page.
Open Reservations and find the booking under Upcoming.
To extend, click Extend permit. Set the New end time and click Extend.
If the extension is not allowed, the reason shows in the window, for example the most extensions or the most extra time the building allows.
To cancel, click Cancel on the row and confirm. The guest gets an email that the parking is cancelled, and the pass stops being valid.