US Secrateries who have been vetoed by Congress?

I'm doing an essay question - "The President is the most powerful person in the USA. Discuss." - and I'm talking about the President's power of appointment. However every point I make I have to show balance and produce a counter argument so my counter is that Congress can veto the President's choice of Secrateries. However I can't find any recent examples of Congress ever doing this. So do any of our American users know of any examples of this?