Preview recurring schedule change
Call this when the consumer changes the Payment Frequency dropdown in the Update Recurring Date modal. The response contains the numbers shown by the preview card: current payment amount, new payment amount, current/new monthly totals, percentage change, and increase/decrease direction. Returns data: null when the requested frequency is the same, invalid, or cannot be previewed for the current plan; the frontend should hide the preview card in that case.
Authorizations
Bearer authentication header of the form Bearer <token>, where <token> is your auth token.
Path Parameters
Consumer account ID.
Query Parameters
weekly, bimonthly, monthly Response
Recurring schedule preview returned.
Numeric preview values for the Update Recurring Date dropdown. Money values are decimal strings so the frontend can format them consistently.

