Hi,
Someone helped my with this yesterday, this might help.
$input date = //where your date is
$input_day = substr($input_date, 0, 2);
$input_month = substr($input_date, 3, 2);
$input_year = substr($input_date, -4);
$ts = mktime(0, 0, 0, $input_month, $input_day, $input_year);
$Newsdate = date('d-m-Y', $ts);
Hope it works, i'm still new, so i'm not 100%