Redirect instead of success message

How do I redirect to say a thank you page if someone fills out this form:

<?php
if(isset($_POST[‘action’])) { // Checking for submit form
$my_email = "jeanette@jeanettekwok.com"; // Your email address
if($_POST[‘action’]==‘add’) {
$name = trim(strip_tags(addslashes($POST[‘name’])));
$email = trim(strip_tags(addslashes($POST[‘email’])));
$subject = trim(strip_tags(addslashes($POST[‘subject’])));
$message = trim(strip_tags(addslashes($POST[‘message’])));
$pattern = '/^[^\W][a-zA-Z0-9
]+(.[a-zA-Z0-9
]+)*@[a-zA-Z0-9
]+(.[a-zA-Z0-9
]+)*.[a-zA-Z]{2,4}$/’;

	if($email != "" && $message != "") {
		if(preg_match($pattern, $email)) {
			$messages	= "Name: " . $name . "

" . $message;
$headers = "From: " . $email . "
";
mail($my_email,$subject,$messages,$headers);
echo “success|<div class=‘alert alert-success’><button type=‘button’ class=‘close’ data-dismiss=‘alert’>×</button>Thank you for your interest in our work. We will get back to you very shortly.</div>”;
} else {
echo “error|<div class=‘alert alert-error’><button type=‘button’ class=‘close’ data-dismiss=‘alert’>×</button>Please enter a valid email address.</div>”;
}
} else {
echo “error|<div class=‘alert alert-error’><button type=‘button’ class=‘close’ data-dismiss=‘alert’>×</button>Please fill all the required fields.</div>”;
}
}
} else { // Submit form false
header(“Location: index.html”);
}
?>

Right now, it shows a thank you message. I need to redirect to a page.
Thanks,

Jeanette