# FX-SCH-A-000351

Source: https://xmlvalid.com/rules/FX-SCH-A-000351

> Only one BT-56 element is allowed on an invoice.

- Level: error
- Rule sets: Factur-X MINIMUM rules 1.09, Factur-X BASIC rules 1.09
- Context: `/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeAgreement`
- Test: `not(ram:BuyerTradeParty/ram:DefinedTradeContact/ram:PersonName and ram:BuyerTradeParty/ram:DefinedTradeContact/ram:DepartmentName)`

Validate a document against these rules: https://xmlvalid.com/validate