def renameMachine(self, machineName, newMachineName):
        """
           You must use this operation if one of the registered machines
           has undergone a name change. This operation updates any
           references to the former machine configuration.
           By default, when the server is restarted, it is capable of
           identifying a name change and repairing itself and all its
           references. This operation is a manual call to handle the
           machine name change.
           Input:
              machineName - The former name of the server machine that is
                            registered with the site.
              newMachineName - The new name of the server machine.
           Output:
              JSON messages as dictionary
        """
        params = {
            "f" : "json",
            "machineName" : machineName,
            "newMachineName" : newMachineName
        }
        uURL = self._url + "/rename"
        return self._post(url=uURL, param_dict=params,
                             securityHandler=self._securityHandler,
                             proxy_port=self._proxy_port,
                             proxy_url=self._proxy_url                             )