Dear Emrah,
I'm not sure the reason you change reference filed but you shall never approach such method.
You can always do account assignment reference transfer for such kind of issue. Please find below link which might be useful.
http://scn.sap.com/thread/3309033
https://help.sap.com/saphelp_globext607_10/helpdata/en/9e/73993a9f6ee076e10000000a11402f/content.htm
Regards,
Jain