- array_reverse: documentation ( source)
- implode: documentation ( source)
- explode: documentation ( source)
- preg_replace: documentation ( source)
<?php
$cell_content = '10-02-2014';
$cell_content = implode('-', array_reverse(explode('-', $cell_content)));
$c2 = preg_replace('/(\d{2})-(\d{2})-(\d{4})/', "\3-\2-\1", $cell_content);
echo $cell_content;
echo $c2;