To Reject a candidate for a position, head into your User's Applications Folder and scroll up to the "Actions" Button and click on "Reject"
Enter in your reason for rejecting and hit submit.
Once you refresh your User Profile Page, the Application for that Position will be marked as rejected.
As of release v3.50, the most recent rejection reason is now shown on the user's profile!
Note: You can turn a rejected candidate into an active candidate by creating an application for them.
A rejected candidate is able to reapply to a position.