Dry run of absorbing source_client_id into this client as a billing profile. Writes nothing; returns the profiles that would move, per-entity row counts, the contacts and contracts needing a decision, the portal users whose billing-segment access would widen, the accounting mappings that would need re-pointing, and any blockers.
Content type: application/json · schema ClientMergePreviewBody
Success response 200 · schema ClientMergePreviewEnvelope
originalcutover