public void UpdateProcessInstanceComment(
	int processInstanceId,
	int commentNumber,
	string message
)

Public Sub UpdateProcessInstanceComment ( 
	processInstanceId As Integer,
	commentNumber As Integer,
	message As String
)

- Update the comment #1 of request #1 (Tag and geolocation data will be reset):
http://yourserver:port/wfgen/ws/ProcessesRuntime.asmx/UpdateProcessInstanceComment?processInstanceId=1&commentNumber=1&message=Hello World!<br />
- Update the comment #1 of request #1 with tag and geolocation data:
http://yourserver:port/wfgen/ws/ProcessesRuntime.asmx/UpdateProcessInstanceComment?processInstanceId=1&commentNumber=1&message=Hello World!&tag=J9FH12TH4&geoLocationLatitude=43.21&geoLocationLongitude=87.65&geoLocationAltitude=1211.109<br />
- Update the comment #1 of request #1 with delegation security access from wfgen_admin:
http://yourserver:port/wfgen/ws/ProcessesRuntime.asmx/UpdateProcessInstanceComment?processInstanceId=1&commentNumber=1&message=Hello World!&delegateUsername=wfgen_admin

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
  class Program
  {
    static void Main(string[] args)
    {
        // Variables
        System.Net.HttpWebRequest httpWebReq = null;    // Http web request object
        System.Net.HttpWebResponse httpWebResp = null;  // Http web response object
        System.IO.StreamReader myReader = null;         // To read response stream
        string url = string.Empty;                      // URL of the web method of the API
        string response = null;                         // string used to display response

        // Call the Web Service API method (replace yourserver and port with your hostname)
        url = "http://yourserver:port/wfgen/ws/ProcessesRuntime.asmx/UpdateProcessInstanceComment?processInstanceId=1&commentNumber=1&message=Hello World 2!";

        // Prepare the request
        httpWebReq = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(url);
        httpWebReq.Method = "GET";
        httpWebReq.Credentials = System.Net.CredentialCache.DefaultCredentials;
        httpWebReq.ContentType = "text/xml; charset=utf-8";

        // Gets the stream associated with the response
        httpWebResp = (System.Net.HttpWebResponse)httpWebReq.GetResponse();
        myReader = new System.IO.StreamReader(httpWebResp.GetResponseStream());
        response = myReader.ReadToEnd();
        httpWebResp.Close();

        // Display the XML in the console
        Console.Write(response);
    }
  }
}

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Net;
using System.Xml;
using System.Xml.Xsl;
using com.mycompany.www;
<br />
public partial class _Default : System.Web.UI.Page
{
    protected RuntimeService myRuntimeService = null;
<br />
    protected void Page_Load(object sender, EventArgs e)
    {
        ProcessInstanceCommentHeader myProcessInstanceCommentHeader = null;
<br />
        // Settings and parameters
        myProcessInstanceCommentHeader = new ProcessInstanceCommentHeader();
        myProcessInstanceCommentHeader.Tag = "J9FH12TH4";
        myProcessInstanceCommentHeader.GeoLocationLatitude = 43.21;
        myProcessInstanceCommentHeader.GeoLocationLongitude = 87.65;
        myProcessInstanceCommentHeader.GeoLocationAltitude = 1211.109;

        // Set NetworkCredentials with the credentials of the current connected user
        myRuntimeService = new RuntimeService();
        myRuntimeService.ProcessInstanceCommentHeaderValue = myProcessInstanceCommentHeader;
        myRuntimeService.Credentials = CredentialCache.DefaultCredentials;
<br />
        // Call the Web Service API method
        myRuntimeService.UpdateProcessInstanceComment(1, 1, "Hello World 3!");
    }
}
<br />