cookie waarden updaten

<?php
setcookie('test', 'ivo;stijn;lien;tine', time()+3600);

$vars = explode(";", $_COOKIE['test']);
echo $vars[3];
?>

<?php
setcookie('test', 'ivo;stijn;lien;tine', time()+3600);
 
$vars = explode(";", $_COOKIE['test']);
echo $vars[3];
?>

<?php
if($_POST['submit'] == TRUE)
{
$vars[3] == $_POST['update'];
}
?>

<?php
if($_POST['submit'] == TRUE)
{
$vars[3] == $_POST['update'];
}
?>