That depends on what you want to do -- if you want to edit the metadata for the citations, that's not possible.
If you want copies of those item (which won't be connected to the citations, though they will have the same metadata) for your Zotero library, you can use https://rintze.zelle.me/ref-extractor/
If you have some Word macro skills, I posted a macro in https://forums.zotero.org/discussion/comment/465655/#Comment_465655, which might help (save a backup first!). You can use it by inserting citations of every item in the new library (those imported from the ref-extractor output) at the end of the document (use multiple source citations from the old style insert dialog - this should result in twice as many listed items in the bibliography), running the macro, and removing the added citations. You can get our group/user library number from the field codes of the fake citations you add to tweak the macro.
Upgrade Storage
If you want copies of those item (which won't be connected to the citations, though they will have the same metadata) for your Zotero library, you can use https://rintze.zelle.me/ref-extractor/