Just to clarify, the order (which is between the dealer and the manufacturer) does not need to be cancelled in order to benefit from a lower AP. All that needs to change is the admin between the dealer and Motability, which takes just a few minutes.
This is an important distinction, as many people wrongly assume that because a car shows as being ‘ordered’ on the Motability system that it has been, when often it hasn’t. This is why some Motability customers wait many months longer than others for the same car, because the dealer has processed the admin with Motability but is awaiting a build allocation slot before actually being able to order the car from the manufacturer. The Motability system effectively just shows that they have authorised the dealer to place an order – not that the dealer has actually ordered it yet!