public function sendChangeNumber($number, $identity)
    {
        $msgId = $this->createIqId();

        $usernameNode = new ProtocolNode('username', null, null, $number);
        $passwordNode = new ProtocolNode('password', null, null, urldecode($identity));

        $modifyNode = new ProtocolNode('modify', null, [$usernameNode, $passwordNode], null);

        $iqNode = new ProtocolNode('iq',
            [
                'xmlns' => 'urn:xmpp:whatsapp:account',
                'id'    => $msgId,
                'type'  => 'get',
                'to'    => 'c.us',
            ], [$modifyNode], null);

        $this->sendNode($iqNode);
    }