PayPal\Service\PayPalAPIInterfaceServiceService::DoVoid PHP Method

    public function DoVoid($doVoidReq, $apiCredential = null)
    {
        $apiContext = new PPApiContext($this->config);
        $handlers = array(new PPMerchantServiceHandler($apiCredential, self::$SDK_NAME, self::$SDK_VERSION));
        $this->setStandardParams($doVoidReq->DoVoidRequest);
        $ret = new DoVoidResponseType();
        $resp = $this->call('PayPalAPIAA', 'DoVoid', $doVoidReq, $apiContext, $handlers);
        $ret->init(PPUtils::xmlToArray($resp));
        return $ret;
    }

 authorization to void or, to void an order, the order ID.
 `Important:
 If you are voiding a transaction that has been reauthorized, use the
 ID from the original authorization, and not the reauthorization.`
*/
$doVoidRequest->AuthorizationID = $_REQUEST['authID'];
$doVoidReq = new DoVoidReq();
$doVoidReq->DoVoidRequest = $doVoidRequest;
/*
 * 	 ## Creating service wrapper object
Creating service wrapper object to make API call and loading
Configuration::getAcctAndConfig() returns array that contains credential and config parameters
*/
$paypalService = new PayPalAPIInterfaceServiceService(Configuration::getAcctAndConfig());
try {
    /* wrap API method calls on the service object with a try catch */
    $doVoidResponse = $paypalService->DoVoid($doVoidReq);
} catch (Exception $ex) {
    include_once "../Error.php";
    exit;
}
if (isset($doVoidResponse)) {
    echo "<table>";
    echo "<tr><td>Ack :</td><td><div id='Ack'>" . $doVoidResponse->Ack . "</div> </td></tr>";
    echo "<tr><td>AuthorizationID :</td><td><div id='AuthorizationID'>" . $doVoidResponse->AuthorizationID . "</div></td></tr>";
    echo "</table>";
    echo "<pre>";
    print_r($doVoidResponse);
    echo "</pre>";
}
require_once '../Response.php';