Pretty url for a custom post type

Hi.
I have created a custom post type ‘professor’. so when I create a new post within that post type with title ‘abc’, the url to that would be something like
http://x.com/professor/abc

But I want to remove ‘professor’ from this url.
Now, It is just able to redirect http://x.com/abc to http://x.com/professor/abc but I don’t want to redirect!

What should I do?