A master page in InDesign is where elements that are going to be used in multiple places within a document (page numbers, borders, etc.) are placed. You can tell if any have been set up in your document by opening the Pages Panel. You'll notice that there is an area above the document pages (the ones that are numbered 1,2, etc). There should be pages in that area that will be labelled [None] and A-Master (unless the person who created the file has retitled the A-Master to something else). If there is a Master Page (or Pages—there can be as many created as needed) then global changes can be applied there and they will appear in all of the document pages as have the Master applied. I'm glad the font solution worked. It is the simpler way to go all around.
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