You can change the name of a folder either in the thumbnail hover view, or on the folder tree to the left of the screen.
- In your library, locate the folder you want to rename in the navigation on the left or by clicking through the folder thumbnails.
- Hover over the folder name or folder you'd like to update.
- Click on the Elipse icon to the far right.
- Click Rename Folder.
- Rename the folder and click Ok.