Web service .ASMX call code behind site

 public string WebServiceCallsession(string username, string methodName)
    {
        WebRequest webRequest = WebRequest.Create("https://pramod.com/Uservalidate.asmx");//http://localhost/AccountSvc/DataInquiry.asmx
        HttpWebRequest httpRequest = (HttpWebRequest)webRequest;
        httpRequest.Method = "POST";
        httpRequest.ContentType = "text/xml; charset=utf-8";
        httpRequest.Headers.Add("SOAPAction: http://tempuri.org/" + methodName);
        httpRequest.ProtocolVersion = HttpVersion.Version11;
        httpRequest.Credentials = CredentialCache.DefaultCredentials;
        Stream requestStream = httpRequest.GetRequestStream();
        //Create Stream and Complete Request            
        StreamWriter streamWriter = new StreamWriter(requestStream, Encoding.ASCII);

        StringBuilder soapRequest = new StringBuilder("<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"");
        soapRequest.Append(" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" ");
        soapRequest.Append("xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\"><soap:Body>");
        soapRequest.Append("<KillSession xmlns=\"http://tempuri.org/\"> <as_user_id>" + username + "</as_user_id><as_flag>DUPLICATELOGIN</as_flag></KillSession>");
        soapRequest.Append("</soap:Body></soap:Envelope>");

        streamWriter.Write(soapRequest.ToString());
        streamWriter.Close();
        //Get the Response  
        HttpWebResponse wr = (HttpWebResponse)httpRequest.GetResponse();
        StreamReader srd = new StreamReader(wr.GetResponseStream());
        string resulXmlFromWebService = srd.ReadToEnd();
        return resulXmlFromWebService;
    }