How to set the phone to be temporarily unavailable, and then prompt by SMS?

First, don't turn off the battery. Incoming time "the other party's phone can't be connected. (it will damage the phone. Secondly, some mobile phones can be realized by manually selecting a network and then selecting another network. But in these cases, the phone is disconnected. Third, use the color ring function to find the color ring of this sound. Mobile phone settings can only be achieved by adding corresponding software to high-end smart phones. Fourth, find a mobile phone number that is out of service or empty, and set it as call forwarding.