No-Show or Cancellation Fee

How is everyone adding fees for last-minute cancellations and no shows? While they are rare, I find they are often missed and the clients are not charged when they should have been. Since the therapists do not have access to billing, is there a way they can add a cancellation/ no-show fee or do I need to continue to do that manually. It would be helpful if there was an easier way to keep track of these.