public function cancel($requestUuid)
    {
        if (empty($requestUuid)) {
            throw new PlivoValidationException(
                "Which call request to cancel? No requestUuid given");
        }
        $this->client->delete(
            "Account/".
            $this->pathParams['authId'].
            "/Request/".
            $requestUuid.
            '/',
            []
        );
    }