Time Zone Conversion

<?php

date_default_timezone_set('Asia/Karachi');
$datetime = new DateTime('2020-09-27 01:47:23');
echo "Pakistan = ".$datetime->format('Y-m-d H:i:s A')."\n<br><br>";
$la_time = new DateTimeZone('America/Los_Angeles');
$datetime->setTimezone($la_time);
echo "Los_Angeles = ".$datetime->format('Y-m-d H:i:s A')."<br><br><br>";


$currentDateTime = '08/04/2010 22:15:00';
echo $newDateTime = date('h:i A', strtotime($currentDateTime))."<br><br><br>";


print gmdate("Y-m-d\TH:i:s\Z");

?>