39. Reschedule with a Replacement Appointment

Status

Accepted for the MVP working model; replacement Appointment, same-payment, same-entitlement, and Admin-only operation are resolved by ADR 0039. Whether reschedule is allowed after each lifecycle state, policy cutoff, approval details, and client notification/recovery remain open.

Context

Editing an Appointment's time in place destroys the original commitment, complicates audit, and can accidentally consume or release a package entitlement twice. Requiring a new payment/Booking for a staff-approved schedule change misrepresents the existing purchase.

Decision

An authorized admin performs a RescheduleAction:

preserve the original Appointment record;
mark it rescheduled with actor/time/reason and link to the replacement;
hold/claim a new AvailabilitySlot;
create a replacement Appointment for the same Booking;
for a package, link the replacement to the same SessionEntitlement and PackagePurchase;
carry forward the existing Payment/financial settlement; no new Payment or entitlement is created;
release the old slot only as part of the atomic successful action.

The replacement must pass the same overlap/concurrency constraints. If the new slot cannot be claimed, the original Appointment remains active.

Consequences

Positive:

original and replacement schedule history are explicit;
package balance is not double-consumed;
financial reconciliation remains tied to the original purchase;
failed reschedule does not destroy the working appointment.

Costs and constraints:

Appointment state and replacement links are needed;
action must be idempotent and transactional across old/new slot;
notifications must distinguish changed schedule from cancellation;
cancellation/refund policy may impose restrictions that admin must see.

Open follow-up

Define allowed reschedule lifecycle states, policy cutoff/approval interaction, and client notification/recovery behavior. Admin-only authority and replacement/same-entitlement semantics are resolved.