You can end your trip through the app or website - once you've parked and locked, taken photos, and completed all the other return steps, hit the 'End trip' button.
When you drop the car back - especially if you're returning early - you should end your trip.
To do this:
- log in (the site or app will be in "trip flow")
- follow the steps to return the car and take photos
- hit the 'End trip' button
If you complete a trip early, the remaining time is considered “cancelled time”. You will still be charged for this time, unless another member books the car. More detail