Solution : https://service.sap.com/sap/support/notes/441857 (SAP Service marketplace login required)
Key words : 
verfügbarkeitsprüfung für material & ist nicht möglich, create variable message v4 247which, terms idoc_input_orders idoc_input_ordchg reason, previous system responseis retained, previous system response, message class v4, changing sales documents, unconfirmed schedule lines, parallel mass processing, message user-dependently
Related Notes : 
       
| 1596256 | |
| 415423 | |
| 402863 | |
| 351365 | SD EDI ORDCHG: Item is not deleted | 
| 206452 | Quantity change in ordered third-party order |