It is not possible to create a credit note for a consolidated invoice or an invoice that is part of a consolidated invoice. You must first revoke the consolidated invoice, after which you can create credit notes for the original invoices.
If the consolidated invoice has not been finalised, you can revoke it and then create credit notes for the original invoices.
If the consolidated invoice has been finalised, you must first cancel the payments. You can then revoke the unpaid consolidated invoice and create credit notes for the original invoices.
If Provet Pay or the Gravity Payments integration was used to pay the consolidated invoice, you can first do a full refund on the consolidated invoice (see refunding Provet Pay payments or refunding Gravity integration payments). You can then revoke the unpaid consolidated invoice and create credit notes for the original invoices.