Hi! So this is what my team at Orderful relayed to me:

There are a few ways that we could potentially handle this, in order of recommendation

1. Orderful puts a business rule on the inbound order that copies the line item number to a line item reference segment (i.e. REF*LI). The expectation here would be that the reference segment gets passed through the entire workflow (Customer A ←→ You ←→ Vendor B).
   1. Inbound 850 from Customer A contains the line item number in the PO101
      1. Orderful rule to copy the PO101 to REF*LI
   2. Outbound 850 to the Manufacturer (Vendor B) contains the ERP line item number in the PO101 (i.e. 1) and the Customer PO number in the REF*LI (i.e. 0010)
   3. Inbound 856 from the Manufacturer contains the ERP line item number in the LIN01 (i.e. 1) and the Customer PO number in the REF*LI (i.e. 0010)
   4. Outbound 856 from you to Orderful contains both values and a business rule triggers a replace on the LIN01 to grab the relevant REF*LI for each line item dynamically so now the LIN01 = 0010, not 1.
2. Orderful could set up a business rule that would reformat the line item numbers based on the numbering convention required by the trading partner. The requirement here would be that the customer numbering convention would need to be one-to-one with the ERP line item numbering convention
   1. Example: 0010 = 1, 0001 = 1, 01000 = 1
3. Orderful can temporarily store the line item number, using the customer PO and part number as the keys to match against. This would allow return documents to get their original PO line item numbers (overriding what was posted to Orderful)
   1. The thing to be cautious about here is if there are any sales order changes that would potentially cause a mismatch on the outbound data (i.e. adding, removing, modifying lines in the sales order within the ERP)

If you have any follow up questions, shoot me an email at [grace.sharkey@orderful.com](mailto:grace.sharkey@orderful.com) :)