Changing the SAP Standard (BC) 
The SAP System provides a comprehensive infrastructure for business computing. To streamline business processes, however, you may be required to make modifications to the standard. You can enhance, modify or reduce the functions provided for a specific environment.
As of
release 7.0 of the SAP NetWeaver Application Server ABAP (SAP NetWeaver
2004s), a new enhancement concept exists in the ABAP Workbench (
Enhancement
Framework), which helps to integrate various concepts for the modification
and enhancement of development objects, and which is intended to gradually
replace the previous concepts.
For information about the modification levels see: