Backorder Processing

Backorder processing is a functionality in SAP where you can change the committments and over-ride the blockage of stocks 
marked against sales documents/deliveries. For e.g. you receive an order from a very important customer for material "A" but 
the entire quantity of A is committed to another customer "B" via earlier sales orders and this is where BACKORDER processing helps you to change the committment and shift stock due for B to A. This is the benefit of this funtionality.

OMIH - Checking rule for updating backorders 
OPJL   - Define new checking rule 
OPJJ   - Define scope of check

V_RA - Backorder Processing

Data selection:- 
Sold-to-party             Customer code            Mandatory 
Sales Organization                                         Mandatory 
Distribution Channel                                       Mandatory 
Division                                                         Mandatory

Changed confirmed quantity :- 
Tick the material you want to changed and click the Backorder button 
Confirmed quantity that still can be changed are highlighted.

V.15 - Backorder List 
Sales Organization                                         Mandatory 
Distribution Channel                                       Mandatory 
Division                                                         Mandatory