In the Modify Style dialog box, look for an option that says "Update automatically." Since I'm not using Word for Mac, I can't give more specific advice, I'm afraid.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional

To clarify, uncheck the checkbox to prevent Word from automatically updating globally. (Stefan, correct me if I'm wrong.) However, as a convenience, you don't need to uncheck the box if, after you apply the change, you press Ctrl-Z to undo. This is because when you apply the change, Word performs a two-step process that looks like it's a single process: 1) it applies the change to the individual paragraph and then 2) it applies the change globally. When you undo, you're undoing the global change. I just read this on a forum, but I can't find it now :-)