When you right click and add service reference in your project, the web.config or the app.config (depending on the project type) will have the below item which can be used for changing configurations.
<endpoint address="http://yourouwn.service.url.com/service.asmx">
binding="basicHttpBinding" bindingConfiguration="ServiceSoap"
contract="SomeNameHere.ServiceSoap" name="ServiceSoap" /></endpoint>