Disbanding atamans

How to? I don't think there's a button to do so, right?

There are traits that are better than others, but they seem to appear in the pool only every now and then.

Is it better to just wait to appoint atamans until the trait you want appears in the pool (I'm assuming they rotate just like new generals), or to suicide the 'bad' ataman against an enemy army when they get close to its city? The suicide tactic works, but it's tricky having the ataman you don't want (it takes a turn to travel) at the right city at the right time.