Solution : https://service.sap.com/sap/support/notes/439742 (SAP Service marketplace login required)
Key words :
additional key words service, account assignment category, reference code pt9b, service item, transaction me51n, longer change, program change, advance corrections, field selection, prerequisites
Related Notes :
| 313120 | ME21N:Accnt assgmt cat fr item cat D cannt be chngd |