# BR-56 Seller tax representative must have a VAT identifier

Each Seller tax representative party (BG-11) shall have a Seller tax representative VAT identifier (BT-63).

## Problem Description

> **ERROR**: EN 16931 core business rule (CEN)

## Context and Significance

This is an EN 16931 core rule. A tax representative acts for a seller that is not established in the member state and must therefore be identified by its own VAT identifier. The error appears when the representative is exported with name and address but no VAT identifier, or with the number placed in cac:PartyLegalEntity instead of cac:PartyTaxScheme.

## Solution

Add cac:TaxRepresentativeParty/cac:PartyTaxScheme/cbc:CompanyID with the representative’s VAT identifier and cac:TaxScheme/cbc:ID = VAT (CII: ram:SellerTaxRepresentativeTradeParty/ram:SpecifiedTaxRegistration/ram:ID with schemeID="VA").

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-56)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-56)

## Valid Examples

- BT-63 = FR12345678901 for the tax representative

## Invalid Examples

- Tax representative party with name and address but no BT-63 VAT ID

## Code Examples

### Valid XML
```
<cac:TaxRepresentativeParty>
  <cac:PartyTaxScheme>
    <cbc:CompanyID>FR12345678901</cbc:CompanyID>
    <cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme>
  </cac:PartyTaxScheme>
</cac:TaxRepresentativeParty>
```

### Invalid XML
```
<cac:TaxRepresentativeParty>
  <cac:PartyName><cbc:Name>Fiscal Rep GmbH</cbc:Name></cac:PartyName>
</cac:TaxRepresentativeParty>
```

## Affected Fields

- [BT-63 Seller tax representative VAT identifier](/resources/xrechnung/bt-63-seller-tax-representative-vat-identifier)

## Related Rules

- [BR-18](/resources/kosit-validator-errors/br-18-tax-representative-name-required)
- [BR-19](/resources/kosit-validator-errors/br-19-tax-representative-address-required)
- [BR-20](/resources/kosit-validator-errors/br-20-tax-representative-country-code-required)

## Validation Tools

- [Official KoSIT Validator](https://github.com/itplr-kosit/validator): Run the official KoSIT validator with the XRechnung configuration to check EN 16931 and XRechnung rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Find validation errors during conversion and review each correction.

## Related Resources

- [Official Specification](https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [All validation errors](/resources/kosit-validator-errors): Overview of the EN 16931, XRechnung and Peppol validation rules explained here.