Acceptance With Grace. The best_case scenario__and honestly, the most common reaction__is that your boss will accept your resignation with understanding and sincere congratulations. Your manager will be happy to see that you're advancing your career and moving on to something bigger and better.
Spot the Signs. Again, you may receive this response if you have specialized knowledge that would make it difficult or time_consuming to hire your replacement__or if it would be helpful for you to be actively involved in that search.