Assuming that you have set up your numbered and bulleted lists with paragraph styles, you can create a template with the desired styles. Be sure to use the same style names as those of your existing document. Then create a new document based on the template and import the existing document via the Insert File dialog box.

To open the Insert File dialog box, do the following: Insert | Object | Text from File. (Note that "Text from File" is misleading; it's actually the good old Insert File command from Word 2003.)

It should be noted that, as far as I know, Microsoft has never confirmed that quick style sets are unpredictable with numbered and bulleted styles. I have seen the problem at a number of times (it may not be 100% reproducable, though).

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional