I booked a car in Palma de Mallorca for today for one day. Can I extend it to two days. I couldn’t get the manage my booking to work. Call me if you like, I am at Stansted Airport.
It's too close to the pick-up date to amend it. Either make a new booking now before you arrive and start it when your existing bookings ends. Make it with the same supplier and location. Then when you collect the car, the supplier will merge the two bookings into one.