Renaming folders in Arduino Uno' SD card
According to this post (https://forum.arduino.cc/index.php?topic=73265.0) this library should be able to rename the folders (https://github.com/greiman?tab=repositories) but there are a lot of posts out there saying they are having problems.

It might be worth checking you can rename them on a PC, there may be problems with name lengths etc that will just complicate matters.