"You're Asking For The Wrong Thing"
It's actually usually a good thing when directs ask for a promotion. Yes, some folks aren't ready, and some folks just want more money, or to make their resume look better for their career planning. But for the most part, people asking for promotions is good. Most managers don't think that, because when a direct asks for a promotion and isn't ready - and most are not - that means we managers have to have a "difficult conversation." We have to, "tell them they're not ready." But that's seeing the glass as half empty. The half full way to think of the conversation is simple: no direct who wants a promotion is assuming they won't get more responsibilities.. The right way to handle this conversation is to tell them that they're asking for the wrong thing - the promotion - rather than the right thing - more responsibilities.