Once you are signed in on JustPark, click on the top left corner and select 'My Bookings'.
Here, you should see all your upcoming bookings. Simply select the booking on which you would like to change the vehicle to be parked, as shown below.
Scroll down the page until you see the subheading 'Vehicle'. 'Change Vehicle' will be towards the right side of the screen in green writing, which you should now tap.
Next, a box will appear on the screen showing you your current vehicle for this parking space, and the option to 'Add New'. You should select this.
JustPark will then ask you a couple of questions about the new vehicle which you wish to choose - this process does not take long!
Once you have filled out these details, click on the big green tick above the keypad and your vehicle will have successfully been changed.
The app will have now updated your new vehicle.