Tom, the best solution depends on how many Events you have to change, and whether you see yourself needing to do this again and again. You might spend less time just doing them one by one than chasing down a batch method and then implementing it for this one task. If this was an undiscovered (by you) feature of iCal, that might be a different story. But, if you can't find it in iCal Help, it probably doesn't exist.