Part of the manager’s job description is to retain the (better part of the) staff. Long-term staff accrue intimacy with the organization’s unique products and services; they are fluent in the local culture and know how to get things done. Naturally, the stars and even the solid players on the team are highly valued, especially by their direct manager whose personal success they most directly impact.
When one of those people comes into your office, closes the door and announces that s/he has decided to leave the team, shock and panic can be the automatic response. The sympathetic nervous system (fight/flight/freeze) is yelling inside your head, “We’re screwed.” You feign composure and then you proceed, on the spot, to try and rescue yourself and your team by changing the employee’s mind. If you have been asleep or disinterested in personal (not personnel) management, this is the first time you have ever asked the person what would bring her true job satisfaction.
If, instead, you have practiced personal management all along, you are not really surprised. Though you could never have predicted the exact timing, you knew this moment was becoming because you, like the employee, appreciate that most of the professional development available to this person in this job has already been realized.
Ethical employee retention is a continuous process and is not so arrogant to think that it possess an employee forever. The best employees are only passing through on their career journey. Pressure, persuasion and bribes at the last minute are disrespectful to the delicate discernment that brought the employee to this point. If you are successful at swaying her, you are not practicing retention, but detention. Detentions tend to be short and the employee leaves anyway.