If your employee is going to leave anyway, your best course of action is to encourage them. Perhaps something along the lines of: "We're really going to miss y

If your employee is going to leave anyway, your best course of action is to encourage them. Perhaps something along the lines of: "We're really going to miss you, but it's clear that this is a great opportunity for you. When it's time for you to move on from that role give me a call... I'd love to chat with you about roles back here that would be a good fit with that additional experience under your belt"