Yes, Spock, in Star Trek III: The Search for Spock, and Zachary Quinto in the new movie.
To that effect then, pretty much the entire cast of the original series; Kirk, Spock, McCoy, Uhura, Scotty)
Picard, Ro, Guinan and Keiko in the episode "Rascals" when they got turned back into kids, Tucker in "Similtude", Captain Braxton was recast in Voyager, I think the Borg Queen was played by a different person in First Contact and "End Game"(or another Voyager episode)
oh and lets not forget daimon bok
Tucker was not played by more then one actor in "Similtude" Sim (Trip's clone) was