Solution : https://service.sap.com/sap/support/notes/437168 (SAP Service marketplace login required)
Key words : 
maintain field bpbp030-name3, business partner conversion, terms business partner, attached correction instructions, activated parallel supply, field name3, bpdadref-name3, field str_suppl1, parallel maintenance, additional data
Related Notes : 
       
| 398888 | BP_TR1: Composite note and FAQs about bus partner conversion |