EFIR modification

[Tomm33]

I have digital photos taken by one member of a group of photographers who failed to set the time correctly in her camera... her time is 12 hours off.. which really screws up sorting by time taken. I've found several programs which will let me batch change the date, and some the time, but none that will simply let me move the time of a group of photos (batch update) by a number of hours... in this case 12 hours to change the PM's to AM's and vice versa.

Any help would be appreciated..