I'm looking for a word that describes the process by which a leader is chosen. I would use "election", but that word contains too much information about the details of the process. I need something that doesn't refer to any particular way of going about the selection process - a general term that encompasses election, appointment, coup d'etat, etc.
Ideally, I'd like something that has both noun and verb forms. A technical, niche, or uncommon word would be okay, but an excessively long word would not be very useful.
One of my intended use cases has the verb form appearing on its own in command form, as a single-word sentence. Another case I have in mind is to use the noun form in a sentence such as, "When members of government realize the old leader is incapable of leading, they begin {the selection process}."