Don't abruptly end the or expect it to fizzle out on its own. That's not fair to your mentor. Once you've decided that the relationship has run its course, choose an end date and plan to meet with your mentor at least one last time. Remember that your professional reputation is at stake, and the way you end the mentoring reputation can impact your career. Tell your mentor that your next meeting will be your last, so he or she can prepare for it.
Prepare for your last mentor meeting ahead of time. If you think nerves may affect you, write down your speaking points before the meeting. You'll want to address several points in this "break-up" conversation.
Start with the good