How to fire Secretary of State Hillary Clinton

Of course, Clinton has not been tapped for the position, but a number of pundits, in what may be a Beltway first, have wondered out loud about how Clinton would be/could be fired as Secretary of State.

Does that strike anybody else as odd?

I honestly don't know the answer to this question (and yes, i spent the prerequisite 60 seconds Googling it), but who was the last Secretary of State who was even fired? I mean, it doesn't strike me as something that's even come up very often in the last 50 years. Yet for some reason, the chattering class thinks it must be pondered in terms of Clinton.