In the basic set there is an NPC, a fighter, who has a Parry reaction that lets him roll 1d6 and reduce damage. I also remember seeing the parry power/action in some beta rules.
I don't (yet) have the PHB—is there something like that? A feat maybe?
I've always liked the idea of parry being for all characters, not just a fighter thing, but I want to know the official rules.