To modify a reservation you must make a new one and cancel the previous one. Make sure you can make a new reservation first before canceling the old one.
In Valet Services: If you have a change in the delivery or pick up time of the vehicle, you need to make a new reservation and cancel the previous one. If you can not make a new reservation (the car park may be full or not allow reservations at the last minute) contact the parking to warn them of the change of time. The contact comes in the reservation confirmation you received by email.
In Parking Services with Transfers: If it is a small change in the schedule of entry or exit to the parking (1-2h) it is not necessary to modify the reservation, as long as this change does not imply a rate change.
You DO NOT need to modify your reservation if the changes affect the details of the vehicle (error in car number plate, brand, model). This data can be updated when the vehicle is delivered.
Check how to cancel a reservation here .