You can make a reservation with your most conservative return date. You can also let us note in the free text field of the reservation form that you may lengthen your stay.
Once you know when you are coming back, you can either send us an email to info@aparcalia.com with your new return details, or contact directly the car park staff, which details are indicated in the booking confirmation that you receive by email.
If you wish, you may also confirm the possibility of extending your stay when arriving at the car park