How to Post a Document with Reference in SAP

Enter Transaction code FB50 in the SAP command Field

In the next screen, Select Goto-> Post with Reference from the SAP Standard Menu Bar 

In the next screen , Enter the Following

1. Enter the Reference Document Number
2. Enter the Company Code the Document was posted
3. Enter the Fiscal Year in Which it was posted
4. Press Enter 

In the next screen,Make appropriate changes in the document

Press Enter , In the next screen , Check the Document

Press Save, to Post the new document