code: public void unregisterService(String serviceName, String providerId) {
          getServiceDirectoryClient().unregisterInstance(serviceName, providerId, disableOwnerError);
      }
docs: Unregister a ProvidedServiceInstance
  The ProvidedServiceInstance is uniquely identified by serviceName and providerId
  
  @param serviceName
  the serviceName of ProvidedServiceInstance.
  @param providerId
  the provierId of ProvidedServiceInstance.