origin_timezone_to_utc.php

<?php

$dateString = '2019-01-21';
$originTimezone = 'America/New_York';

$date = new DateTime($dateString, new DateTimeZone($originTimezone));
$offset = $date->getOffset();

$utc = new DateTime($dateString, new DateTimeZone('UTC'));
$interval = new DateInterval(sprintf('PT%sS', abs($offset)));
if ($offset <= 0) {
   $utc->add($interval);
} else {
   $utc->sub($interval);
}

echo "$originTimezone: " . $date->format('Y-m-d H:i:s e') . "\n";
echo 'UTC: ' . $utc->format('Y-m-d H:i:s e') . "\n";