You can change the display name of a document at any time, the name of the original file in the application will be preserved. You can always see the original name in the properties of a document.
This is how it works
- Select the document you want to rename in the file list.
- Click on Edit > Properties in the document options.
- Enter a new display name for the document.
- Click on Save to apply the new display name and close the dialog.