If you are wanting to return your car rental out of hours you need to gain approval by the car supplier. If you run into any issues when you are returning your car rental, don't stress, just call up the provider and ask them what to do. Returning your car hire after hours is a very common occurrence that they are aware of. You do need to make sure that the car supplier is aware of your return time. If you are returning your car at the time that is written in your booking, there will be no issues. If you are returning your car late and have not notified anyone, there will be a problem. To avoid this, let the car supplier know as soon as possible of any delays in your estimated travel time and they will be able to sort something out with you. Ensure that you park in the correct location and that you have locked the car. Proceed to follow the instructions given to you by the supplier on what to do.
Read more about everything you need to know about returning a rental car.