You don't want to change the names of Geometry files or folders. Poser will go nuts if it can't find that stuff. You can change the names of the folders within the Libraries. Example: change "Morphing clothes" to "Mike's Clothes." You can change the names of individual items within Libraries. Example: change "Michael's Shirt" to "Mike's shirt." You could change the names of Texture folders if you got the free version of CorrectReference (CR). You might not want to go through all that work. CorrectReference Pro (CRPro makes everything much easier. But you have to buy it.)