Proxy classes generated using Wsdl.exe will set a default Url property for the client to use. The default Url is determined by the location attribute found in the service description from which the proxy class was generated.
// Set the URL property to a different Web server than that described in the // service description.
math.Url = "http://www.contoso.com/math.asmx";
int total = math.Add(Convert.ToInt32(Num1.Text), Convert.ToInt32(Num2.Text));