Hi,
The only way I know how to do it is a bit complicated.
I made a very quick youtube video showing how to do it: https://youtu.be/ntSOVn_LUBc
(sorry mouse was acting weird during recording)
Basically you have to download this program and install it:
http://archive.editix.com/download.html
Once it’s installed, open it and go to file → open and select ‘all files’ instead of ‘xml files’ then select your libreoffice office document and open it.
On the left you should see a file called ‘settings.xml’, double click on it. Press Ctrl+F and search for ‘PrinterName’ and press enter. Then use the right arrow key on your keyboard and keep pressing it until you see the name of your printer. It should look something like this:
<config:config-item config:name="PrinterName" config:type="string"/>THIS IS YOUR PRINTER
Just delete the name of your printer and press Ctrl +S to save the file.
Now you can exit the program and the file shouldn’t contain your printer name anymore. Don’t open it though because that might add the printername again.
If I didn’t explain it well, or you have questions, feel free to ask