By exporting the goods from Slovenia exportation documents are a base for fulfil VAT returns in Slovenia. In case of any change after the exportation was made, exportation documents shall be amended according to customs legislation. Therefore, the exportation of goods and any later change (for example a credit note) shall be report to box 11 of VAT return. The invoice and/or a credit note shall just be kept as attachments to these documents as an additional proof.
Source Aleksandra Heinzer