A cancelled session is not automatically a lost session. Between the cancel and the write-off there is a sequence of compliant options: the child's own team, the wider consented bench, minutes moved onto sessions already on the calendar, a caregiver-training hour under a different code, and an honest miss when nothing legal fits.
This pillar collects the operational detail behind each of those options: what the payer rules actually allow, what the family gets to decide, what the schedule can absorb, and how a clinic measures the difference without inventing a number.