I added a refernce of ParenerAPI in my projects. and calling SoapClient by passing its user name and password.
But I am getting an error " Request was made to the incorrect endpoint."
Is there any token I would have to pass.
You need to check what location your MC instance is on. Find this in the URL mc.[ ].ExactTarget.com
Use the matching endpoint connection your development environment:
I believe the endpoints have changed. I can't post more than two links, but I had to use https://webservice.s6.exacttarget.com/etframework.wsdl on an s6 instance. If any of the endpoints in Kelly J Andrews' answer don't work, try changing the Service.asmx to etframework.wsdl