How to update the reference date of a posted journal?

Hi,

   While we posted a reversal transaction, forgot to update the reference_date. Is there a way to update the reference_date of a posted journal?

   This is affecting our the staturoty report.   The journal was posted for DEC-12 period while the referenc date was supposed to have 11-mar-2013 date. This way the journal would get reported in MAR-13 period. But since the reference_date was not assigned the correct date while posting, the journal is appearing in DEC-12 period in the statutory report.

Any hepl on how to correct the reference_date would be appreciated.

Thanks

Chidambaram