$action = @$_GET['action'];

AT THE VERY TOP:

$action = @$_GET['action'];

switch($action)
{
 case "edit":
 $edit = true;
 break;
 default:
 $edit = false;
}

THEN in the HTML itself...

if ($edit = true) {
	// SHOW THE EDIT FORM
} else {
       // SHOW THE REGULAR CONTENT
}