I told my program director (I was in emergency medicine) when I had decided that I definitely wanted to switch, but BEFORE I had made any serious inquiries into other programs. I thought he really should hear it from me first before it got back to him through others...but it probably depends -- do you think that your PD will be supportive??? I was really lucky in that I really liked and respected my PD, and he was so great about it, very helpful. I think that it is best if you can leave under good terms...which was why I finished the year (I decided last september). Best never to burn your bridges!!!