(1) A payment transaction is effective vis-à-vis the payer only if the payer has consented to it (authorisation). Consent may be granted either as an approval or, if agreed in advance between the payer and their payment service provider, as a subsequent approval. The modalities of granting consent are to be agreed between the payer and their payment service provider. In particular, it may be agreed that consent may be granted using a specific payment instrument.
(2) Consent may be withdrawn by the payer by making a declaration towards the payment service provider as long as the payment order is revocable (section 675p). Consent to execute a series of payment transactions also may be withdrawn with the effect that any future payment transaction is to be considered as unauthorised.