You can do what they call air- layering. Get a sharp knife and make a cut about 1/4 of the way through the stem diagonally either up or down. Put a matchstick or something similar in the cut to keep it open. Get some damp sphagnum moss and place it around the cut. Get some plastic wrap and place it around the moss and twist-tie both ends to keep the plastic wrap in place. Hopefully in a few weeks you will see roots coming through the moss. You can make the cut anywhere on the plant. It just depends on how big a plant you want. The old plant will also make buds so you will have 2 plants. It sounds like a little work, but if you like the plant it is worth it.