Change format from string datetime

change_datetime_format.php

<?php
/**
 * Change format from the datetime
 * Example: changeDatetimeFormat('2014-11-02 09:11:00', 'd/m/Y H:i:s a');
 * 
 * @param string $datetime String datetime
 * @param string $format String datetime format
 * @return string
 */
function changeDatetimeFormat($datetime, $format = 'Y-m-d H:i:s') {
    return date($format, strtotime($datetime));
}