[Koha] changing date format

[Mary W. Maina]

Hi all,

 i need to change the date format in the system from  mm/dd/yyy to
dd/mm/yyy but this is the system preferences are set with the warning

"PreferenceValue dateformat *(modified)*
Format dates like
.

* Note: Do not change this preference on a production server with overdue
items that are accruing fines. Doing so will result in duplicate fines! *
so please some help here,how do i ensure this does not happen

*?*
Kind Regards,
 Mary