I'm not positive how you have your form set up to email, but I use this for mine and when I click 'reply' it replies it to the email provided. Feel free to take, modify, and implement as you feel the need:
$message = "Greetings <B>" . $ini['administrator'] . "</B>,\r\n\r\nA user has requested access to the Administrative Control panel via the Transcendence page.\r\n\r\nThe Users Info is as Follows:\r\n\r\n<B>Username</B>: <I>" . $_POST["username"] . "</I>\r\n" . "<B>Email</b>: <I>" . $_POST["email"] . "</I>\r\n" . "<B>IP Address</B>: <I>" . $_SERVER['REMOTE_ADDR'] . "</I>\r\n" . "<B>Hashed Password</B>: <I>" . $theHash . "</I>\r\n\r\nConfirm with the User that they have requested this access. If they have, please go to the .htpasswd file and uncomment their hashed password to give them access. Thank you!\r\n\r\n\r\nTranscendence\r\n" . $ini['siteName'] . " at It's Finest";