I think this might solve it:
1. Rename the library folder (by default named "MusicBee" and located at C:\<username>\Music\MusicBee) to what you want the library to be called.
2. Run MusicBee. It'll say that your library can't be found and you need to relocate it.
3. Select your library file in the renamed folder to relocate it.
Let me know if it works