如何在PHP中将当前服务器日历日期更改为另一个日历日期？

I'm gonna change current date to new date in php, In following code current date shows on page in Persian calendar, but it doesn't change real Gregorian date.

For example: If we stored date: 2015-01-03 in database, this code convert this date to new date in Persian Calendar and it will show it on page.

enter image description here

public static function localDate($date = "")
{
    $local = "";
switch (strlen($date))
    {
   default: // Ymd
      {
      if (( $date < '19700101'))
      {
    $local = $date;
    break;
      }
      else
      {
        header('Content-Type: text/html; charset=UTF-8');
        require_once dirname(__FILE__) . '/jdatetime.class.php';
        $local = jDateTime::date("l j F Y", strtotime($date), true, true, 'Asia/Tehran');
        break;
      }
    }
    break;
}
return $local;

}

Here is jdatetime.class.php

Question: How can I change current date to new date in server? I'm gonna store date based on Persian Calendar How to changed server date from Gregorian to Persian calendar?

Here's sample of my problem:

enter image description here