You can change the name of a file or a folder after it's been uploaded.
Editing a file name
Locate the file in the 'Files' section of your workspace and click on its title.
When the file's detail page loads, click on the file name in the top left corner.
Now you can add the new name. Just click away to save the new name.
Editing a folder name
Locate the folder in the 'Files' section of your workspace and click on its 'Options' button.
Select 'Rename' from the drop down menu.
Add the new folder name to the pop up box and click 'Update'.