I've never actually done it,but you're supposed to look for separate crowns and divide at that point - instructions in the link below

http://homeguides.sfgate.com/split-african-violets-91298.html

I would never do that, the stems and leaves are just too brittle, they crack very easily and just handling the plant for that purpose has the potential for ruination. Now if you have new growth crowns, separate these from the mother plant with a sharp small knife or box cutter and this can be done without having to remove the plant from the pot. Then dip the cut bottom of the new crown in rooting hormone and place in starter soil or vermiculite. These plants are also easy to propagate from a single leaf with stem if propagation is your intention. If it is getting large and root bound in its present pot and you cannot transfer it to a larger one, start feeding it African Violet fertilizer on a regular basis and it will give you all that it can for quite a few years more if you tend to it well removing old growth and spent flowers as needed.

Ask Bathgate, he grows a lot.

Thanks Stera.

Hi Wells, it's a fairly simple operation. You'll need a smallish pot, sharp knife, potting soil, african violet fertilizer.

Remove entire plant from pot, clear away as much potting soil as posssible & cut away any soft mushy leaves. You should be able to tease apart the various plantlettes. If necessary use the knife to cut through the root stock to help separate the plantlettes. Then just pot up each plantlette in a smallish pot. They like to be rootbound and will not flower if the pot is too big. Feed each plantlette. They should flower in a month or two. Here is a blog i wrote you may find helpful.

http://www.growsonyou.com/bathgate/blog/27981-success-with-african-violets

Thank you, Bathgate. I am just at the point of doing this. I imagine it would be the same procedure with repotting geraniums except there are no plantlettes. It has taken me a while to get to your explanation and now will go to the website. Thanks again, and will also say,your photos are the BEST.

Thank you Wells. You really made my day. I'll just add that African Violets like to be "pot bound" or they will sulk and not flower for you. So think smallish pot - about 1 inch wider then the root ball. Thanks and Happy New Year!