PHP loop back through an if statement after SQL update - php

Question

I'm trying to figure out a way to loop back through an if statement if the user fills in the the missing fields that updates the database? I was thinking of setting the header location back on it's self but I don't think that will work. Any suggestions please?
<?php
if(!isset($_SESSION)) { session_start(); }
if(!isset($_SESSION["loggedin"]) || $_SESSION["loggedin"] !== true){
header("location: ../login.php");
exit;
}
require_once "../config.php";
$key = $_SESSION["key"];
if (empty($key)) {
$example = $website = "";
$example_err = $website_err = "";
$conn = $link;
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
if($_SERVER["REQUEST_METHOD"] == "POST"){
if(empty(trim($_POST["example"]))){
$example_err = "Please enter a valid key.";
} else{
$example = trim($_POST["example"]);
}
if(empty(trim($_POST["website"]))){
$website_err = "Please enter website URL.";
} else{
$website = trim($_POST["website"]);
}
if(empty($website_err) && empty($example_err)){
$stmt = $conn->prepare("UPDATE users SET website=?, example=? WHERE id=?");
$stmt->bind_param("sss", $param_website, $param_example, $param_id);
$param_website = $website;
$param_example = $example;
$param_id = $_SESSION["id"];
$stmt->execute();
$stmt->close();
$conn->close();
if($stmt){
*DO SOMETHING HERE*
} else{
echo "Something went wrong. Please try again later.";
}
}
}
} else{
echo "Success!";
}?>

Answer 1

If the form is on the same page, please set the form action as
<form action="" method="post">
and if not in the same page, please replace the following:
*DO SOMETHING HERE*
with
header("Location:".$_SERVER['HTTP_REFERER']);