You can set a cancellation fee in the system that will be charged to the customer when you have to cancel a booking.
It's a good idea to display your cancellation policy during checkout and in your emails and documentation, so your customers will know the policy when booking. You can add your cancellation policy to the Terms & Agreements section of the system.
To setup your cancellation fee, go to Settings - Configuration - Orders.
On the Order Settings, select the Cancellations tab.
Enter the Default Fee. You can select a flat fee or a %. Select if the Cancellation Fee is taken from the Subtotal (pre-tax) or the Total Amount (subtotal + tax).
Save your changes.
Once set, when a booking is cancelled in the system, the cancel order screen will default to the pre-set cancellation fee. You will have the option to change the fee or remove it as needed.