If you only need to change the IP address of the controller here is a snippet for that:
luup.set_attr("ip", "192.168.0.1", Device ID)
You can run this command by going to: Apps→ Develop Apps→ Test Lua Code, enter the line from above into the field and press GO.
You just have to replace ?192.168.0.1? with the desired IP Address and replace Device ID with the ID of the device.