event after password change

Using the simple email after an event code I am having a problem. I want to send an email to the user after a password change.
The simple email code:
// ** Send simple email ****

$email="test@test.com";

$from="admin@test.com";

$msg="Hello there\nBest regards";

$subject="Sample subject";

$ret=runner_mail(array('to' => $email, 'subject' => $subject, 'body' => $msg, 'from'=>$from));

if(!$ret["mailed"])

echo $ret["message"];
My problem is what the correct substitution would be for the text that is red which i assume would send the email to the user. My table that records the passwords is titled USERS. The fields in that table are username, password, email and customer number.
Great program, learning fast!