Updates a supplier provider; send only the fields you want to change inside supplier_provider. Unless update_supplier_provider_token is false or you set connection_status, Zuper re-authenticates with the supplier before saving (for SRS it also re-validates the customer account) and marks the provider CONNECTED, so this is also how you reconnect a provider showing RECONNECT_REQUIRED. SRS needs no credentials to reconnect; ABC Supply and QXO usually need a new refresh_token. Setting is_active to false disconnects the provider and clears its stored supplier tokens, so reactivating an ABC Supply or QXO provider requires a new refresh_token in the same request. The response returns only the provider's UID. Requires supplier integration to be enabled for the company; otherwise the request fails with 400. Admin only: the API key must belong to an admin user; other roles receive 405 Access Denied.