List the change events
Consider full and partial cancellation, full and partial refund, item replacement, order edit, payment reversal, fulfillment exception, and return after incentive delivery. Not every event requires the same response.
Define recalculation rules
State whether remaining items still satisfy product and order conditions, which value and time references apply, and when the decision becomes final. Avoid discretionary treatment without documented criteria.
Prepare customer explanations
Use plain language that connects the order change to the published condition. Provide an escalation route for genuine data or processing errors and preserve the decision record.