Can change object but can't write over it

changeObjectFunction.php

<?php

$response = new stdClass();

echo '1): ' . spl_object_hash($response) . PHP_EOL; // 0000000021e89fcd00000000e93b17ba

call_user_func_array(function($response) {
	$response = new stdClass();
	echo '2): ' . spl_object_hash($response) . PHP_EOL; // 0000000021e89fcf00000000e93b17ba
}, array($response));

echo '3): ' . spl_object_hash($response) . PHP_EOL; // 0000000021e89fcd00000000e93b17ba

call_user_func_array(function($response) {
	$response = new stdClass();
	echo '4): ' . spl_object_hash($response) . PHP_EOL; // 0000000021e89fcf00000000e93b17ba // hash descoped and reused
}, array(&$response));

echo '5): ' . spl_object_hash($response) . PHP_EOL; // 0000000021e89fcf00000000e93b17ba