- date_create: documentation ( source)
- timezone_open: documentation ( source)
- date_format: documentation ( source)
- date_timezone_set: documentation ( source)
<?php
$date = date_create('2018-07-17T20:00:00Z', timezone_open('UTC'));
echo date_format($date, 'Y-m-d H:i:sP') . "\n";
date_timezone_set($date, timezone_open('America/New_York'));
echo date_format($date, 'Y-m-d H:i:s') . "\n";