I recently replaced my toilet and found that the metal flange broke. How would I replace the flange and how difficult would the procedure be?

I recently replaced my toilet and found that the metal flange broke. How would I replace the flange and how difficult would the procedure be?

Why replace the flange if all that's wrong is a broken slot. The make a flange repair kit, (see image) for just this sort of problem. Pick up one at your local hardware store. Good luck, Tom