REVEREND IS A TITLE OF RESPECT to be used only in third person, if then. Speak about the Reverend Susan Smith if you have to, but never go up to her and say, "That's telling them, Reverend!" any more than you'd go up to a senator and say, "How are things in Washington, Honorable?"
Reverend means "to be revered." Ministers are not to be revered for who they are in themselves, but for who it is they represent, just as the Spanish ambassador is seated at the hostess's right not because of his beaux yeux, but because he represents the king.