How to modify "unknown author" in track changes

Did a fresh install of LibreOffice, then opened an existing document in Writer and started editing, with “Record Track Changes” turned on.

After a lot of edits, I noticed that all my changes were signed “unknown author”.

To fix this, I entered my information via “Tools > Options > User Data,” with “Use data for document properties” turned on.

Now, all subsequent changes I made to the document do indeed have the proper author information, but all my previously existing changes still have “unknown author.”

Is there some way to fix this, so that all my changes have the same author information?

Thanks for your help.

Version: (x64)
Build ID: 64390860c6cd0aca4beafafcfd84613dd9dfb63a
CPU threads: 8; OS: Windows 10.0 Build 19042; UI render: Skia/Raster; VCL: win
Locale: en-US (C); UI: en-GB
Calc: CL

No way to do that using UI; you would need to edit XML inside the ODF, replacing <dc:creator>Unknown Author</dc:creator> with <dc:creator>Known Author</dc:creator>.