Most (all?) stem plants you can do this with. When re-planting the trimmed parts remember and cut off the leaves towards the bottom so that they dont rot under the substrate. The old stem will probably sprout new shoots at the cut, often two or three, which can either be useful or unsightly. There isn't actually very much information with regard to pruning, I think its just trial and error. Ive made a right mess of some plants that have been growing nicely, tried to trim and re-plant to bush them out and its turned into a stragly mess. Im sure some other people will have some more ideas on this.
