Question : What is the impact of recreating an OU certifier on current users?

Our company had a certifier for users west/acme. I have the original O certifier /acme, but the certifier for the OU is lost. If I already have folks on the OU west/acme and re-create the certifier using the O /acme to establish new users, what impact will that have on the current users established under that old OU certifier?

Answer : What is the impact of recreating an OU certifier on current users?

If you are using the certifiers within your own system only (not cross certifying with other domino systems), then I would just create the new OU certifier, and re-certify all the old users under that OU.  I did this years ago when I moved a large organization from a 3-level OU structure to a 1-level OU structure.