Mark Reisman and Dan O'Shannon have been named executive-producers for NBC's 'Frasier.' The two will replace Christopher Lloyd, who announced last spring that he is departing the post. Most recently, Reisman served as a Frasier consultant for its 1998-99 season, rising to consulting producer this year. Previously, he worked as executive producer for three seasons for NBC series Wings and was a producer on Paramount's Dear John. O'Shannon joined Frasier last year as a co-executive producer. Prior to that, he created and executive-produced Lifetime Television's Maggie.