There is no 24 hour rule with POS France and many others in Europe (if not all others in Europe).

The Platinum line will often gracefully cancel if the request is done before midnight of the day of booking, as the payment will not have been processed.

Passed midnight, it becomes harder to obtain this "geste commercial", but if they want of course they can.

It is more complicated for them though, as they have to justify the gesture; whereas when done before midnight, it flies under the radar.