try
        {
        NetworkCredential credentials = new NetworkCredential("XXXXX", "XXXXX", "XXXXX");
        Workflow workflowSPWebService = new Workflow();
        workflowSPWebService.Credentials = credentials;// System.Net.CredentialCache.DefaultCredentials;
        workflowSPWebService.Url = ParseURL("SPSite URL") + "_vti_bin/Workflow.asmx";


        System.Xml.XmlNode taskDetails = workflowSPWebService.GetWorkflowTaskData("~/_layouts/listform.aspx?ListId=" + "0F61808F-C5A2-4357-BF6B-3F93552BEF5C", 28, new Guid("0F61808F-C5A2-4357-BF6B-3F93552BEF5C"));



        StringBuilder xmlBuilder = new StringBuilder();

        xmlBuilder.Append("<my:myFields xmlns:my="http://schemas.microsoft.com/office/infopath/2003/myXSD" >");

        xmlBuilder.Append("<my:TaskStatus>" + "Approved" + "</my:TaskStatus>"); //Approved || Rejected
        xmlBuilder.Append("<my:Status>Completed</my:Status>");
        xmlBuilder.Append("<my:PercentComplete>1.00000000000000</my:PercentComplete>");
        //xmlBuilder.Append("<my:Completed>1</my:Completed>");
        xmlBuilder.Append("</my:myFields>");

        XmlDocument doc = new XmlDocument();
        doc.LoadXml(xmlBuilder.ToString());


        var sdf = workflowSPWebService.AlterToDo("~/_layouts/listform.aspx?ListId=" + "0F61808F-C5A2-4357-BF6B-3F93552BEF5C", 28, new Guid("0F61808F-C5A2-4357-BF6B-3F93552BEF5C"), doc.DocumentElement);
      //isEmailProcessed = true;
        }
        catch (System.Web.Services.Protocols.SoapException ex)
        {

            throw;
        }