And that's really easy. From there, go ahead and pull it out of the pot. This will dry out, then, for about two months. Keep an eye on it, but let it get nice and dry before you do re-pot it. After that time, go ahead and give it a new pot, new soil, and if you're lucky, you'll get a new bloom, as well, on that.
Geraniums are another one that people like to bring in.
You can do that with cuttings like you do with the impatiens, but another nice way is to go ahead and dig up the plant, roots and all. Get in there. Shake off any extra soil that you might have on it. Then, remove the blossoms and put it in a paper bag. Right in the bag, no soil, no nothing.