See here what to do, specially for Valet Parking Services

If you hire a Valet service, please be as accurate as possible when specifying the vehicle drop-off and pick-up times at the Terminal in your reservation. This will ensure shorter waiting times for the parking staff and a better service.

If already on trip, you think you are going to arrive sooner or later than expected, please phone the parking staff who is waiting for you. The contact details are indicated in your reservation.

In the case of car parks with shuttle services, the time of entry or exit to the car park is indicative. Thus, you can book also though you may not know it accurately.