installed libre office but want to go back to MS Office
No, uninstalling LibreOffice will not change any existing file.
There is no need to uninstall LibreOffice. You can use MS Office parallel.
You might need to tell your operating system, which application it should use, when you double-click a file. I don’t know, whether the installer of MS Office will ask you and do it for your.
The file formats docx and odt have small differences and the export and import filter of MS Office and LibreOffice might convert good or not so good, depending on the document. Therefore I would not uninstall LibreOffice. So you can try case-by-case, whether the export of LibreOffice to docx is better than the import of odt in MS Office or not. Both applications can handle docx as well as odt.
Would you mind telling us, which aspects of MS Office are better for you than LibreOffice?
It got complicated because Word 2010 showed up as an app in the start menu but not in program files so it didn’t show up as an option as a default for .doc files. Uninstalled Office 2016, no help. Uninstalled Libre, no help. Uninstalled Word 2010, reinstalled, finally worked ok.
No particular issues with Libre - - just new/unfamiliar and no apparent advantage over what I was used to.
Thanks for responding.