Typically, matrix children are automatically linked to a vendor. It is assumed that the matrix header knows the primary vendor. PFW can correct the links and supply them if they have not been used before
1) check the matrix header - highlight the matrix header and assure that the vendor is selected and flagged as primary. (Open the Vendors tab at the bottom of the Inventory List)
2) edit the matrix header
3) choose Sync To Matrix Header
4) checkmark Primary Vendor and possibly \"Remove Old Vendor Inventory\"
5) choose Process F10 (this usually makes the changes)
If you have several matrix headers and children needing to be changed, complete step #1 above for each matrix header. Then go to Inventory: Maintenance: Verify Inventory Files. You will be checking
--- Verify Vendors
--- Verify Matrix Headers