Noel,
How many points are we talking about here? We had a similar change-over in our state years back with many lingering NAD27 reference points out there (necessary for basic digitizing). This may have simply been a function of our state plane coordinate system, but we were able to use some simple math to adjust the coordinates datum when needed. It all depends on how many points and how cumbersome its going to be to input them in a table, or if that's even needed...because if its not its likely going to be simpler to attack it from a different angle.