Even a chat-bot could be designed to plead for its "life".

Perhaps a new version of the Turing test is in order. Two computer programs, each pleading for their continued existence. The human judge/executioner is able to interact with both and has two kill switches, one for each. If one of them isn't turned off in 20 minutes, both will be turned off.

What if the machine hires a lawyer to represent it?

So on the up side, I think turning it off would be the same as putting it to sleep. The question is do you ever turn it back on...