Occasionally a department may make a sale to a customer who operates 'self-billing'. This is a restricted scheme where HM Revenue & Customs have given written permission for the customer to tell their supplier how much they are due to pay and to raise the corresponding sales invoice to themselves on the supplier's behalf. It is prevalent in the agricultural and publishing sectors. For example, it is not until the customer weighs a delivery of grain that either them or the farmer knows exactly how much has been delivered and hence needs to be invoiced for.
If you are dealing with a customer who self bills then you must not issue another sales invoice on UFS. Instead please contact the AR helpdesk for further guidance.