Fortunately I asked for four letters of recommendation for my PhD applications. One of the four has not sent any letters in and has not responded to my emails asking about them. Since all of the schools that I applied to require a minimum of two or three, I don't believe my applications are in peril. I'm just wondering if I should rescind the letter requests for this professor. Do you think it would reduce my chances of admission if I were to not rescind the letter (so I would just have an unreceived fourth letter)? Or would it be better to remove the recommender from the list?