Operant conditioning explains how consequences lead to changes in voluntary behavior

Even though you know the mirror won't hurt,you jump out of the chair and run,screaming from the room.When you went to get a shot,the words, This won't hurt a bit,became a conditioned stimulus when they were paired with pain of the shot,the unconditioned stimulus,which was followed by your conditioned response of getting the heck out of there.Classical conditioning in action.Operant conditioning explains how consequences lead to changes in voluntary behavior.So how does operant conditioning work?