Wow - it's been a few years since I've used the CC2 Pro (I've been using CC3) or looked at the FR Atlas for that matter. If you have CC2/CC2 Pro, you probably have to unfreeze the GRID layer in the map and then you can delete the existing grid. And now I honestly can't remember what the grid drawing tool was like or how it worked in CC2...

Sorry I can't be of much help...