Returns what a plan change would charge the company's card on file today, and when the plan would next renew, without making the change. A preview exists only for a company charged by card (the offering's charges_card is true). A company you bill yourself is not charged by card, and a company billed directly by the platform cannot be changed through your key, so a private-label key gets a 422 for either; what you charge your own companies is yours to compute from the offering's prices. Takes the same plan and job_tier_id as plan_changes. Users need the AccountManagement permission. Integration-partner keys are refused.