C# Editing data in SOAP server using WinForms

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C#

SOAP

Hello,

I have a server which is using a SOAP technology. It contains of forms and e.t.c. Also I have an application which find and replace text in files (in XML files) and save changes in new file. So, I need to call my server using application and replace the text in XML form and save it in my PC.
Here is the link of the same program+source. The difference is that my program has one more button, which is using to call server. This is code's part of my version:

private void button1_Click(object sender, EventArgs e)    
{                                                                                           Services.SAPUserInfo myObj = new MassFindAndReplace.Services.SAPUserInfo();        Services.Service s = new Services.Service(); 
            myObj = s.SAPgetUserInfoAll("2500036077");  }

Here is a part of XML:

<my:lg_code xmlns:my="#unknown">2500036077</my:lg_code>

For example, my program will find "2500036077" and will replace it to another string and will save the document in my pc. I added the web reference to my win form, and pasted the url of my intranet to it. So, now I am connected to server. But I don't understand how can I provide a data from server with my program?
I am a beginner in web services and C#, please help with this problem. Thank You.