}
if ($_POST['action'] == 'authorize') {
    // Create the parameters array to set the order
    $requestParameters = array();
    // Required parameters
    $requestParameters['amazon_billing_agreement_id'] = $_SESSION['amazon_billing_agreement_id'];
    $requestParameters['mws_auth_token'] = null;
    $requestParameters['authorization_amount'] = '1.99';
    $requestParameters['authorization_reference_id'] = uniqid('A01_REF_');
    // Optional parameters
    $requestParameters['seller_authorization_note'] = 'Authorizing and capturing the payment';
    $requestParameters['transaction_timeout'] = 0;
    $requestParameters['capture_now'] = true;
    $requestParameters['inherit_shipping_address'] = true;
    $requestParameters['seller_note'] = 'sample for Recurring Payment';
    $requestParameters['seller_order_id'] = '1234-RecExample-Order';
    $requestParameters['store_name'] = 'Saurons fair in Mordor';
    $requestParameters['custom_information'] = 'Awesome Sample';
    $requestParameters['soft_descriptor'] = null;
    $requestParameters['platform_id'] = null;
    $requestParameters['mws_auth_token'] = null;
    $response = $client->authorizeOnBillingAgreement($requestParameters);
    // Display the Billing Agreement Details Result with the bwlo parameters
    $requestParameters = array();
    $requestParameters['amazon_billing_agreement_id'] = $_SESSION['amazon_billing_agreement_id'];
    $requestParameters['address_consent_token'] = $_SESSION['access_token'];
    $response = $client->getBillingAgreementDetails($requestParameters);
    // Convert the response to Json
    $json = json_decode($response->toJson());
    echo json_encode($json, JSON_PRETTY_PRINT);
}