[NTLDR]

Here is the basic code to go on: In the form HTML make the file the form submits to the same as the file thats displaying the form and make sure this hidden input field is added:

<input type="hidden" name="action" value="update">

Then in your PHP, near the top before you do the stuff to display the form:

PHP Code:

if ($_POST['action'] == 'update') {
    // your code here to process the form data, which is in the $_POST array
    // your query

    // lets redirect the user -- make sure your change the url
    $url = "URL_TO_REDIRECT_TO";
    // replace PHRASE_NAME with a title for the phrase you want to show, ie the thanks message and add it to the Front-End Redircet Message group
    eval(print_standard_redirect('redirect_PHRASE_NAME'));
}