I created a PDF from a Word document that used Cambria font, and when I select it in Acrobat to try to change the font I get "The change to a different font was not done because the chosen font and the font encodings in the document differ and could not be resolved"
How can I change the font and why is it preventing me from doing so?
The type of font encoding used has to match. Acrobat does not use fonts in the same way as a word processor. However, the simplest way to make this change and retain your layout and such is to make the change in your WORD document and create a new PDF. Trying to make such changes in the PDF is not an efficient workflow process.
No, Acrobat is not a word processor.
More to the point Acrobat lets one "work" PDF and PDF is not a file format designed as a word processing, editing, formating, or page layout file format.
PDF is, essentially, a "final destination" format.
What it is is described in the ISO Standard for PDF (ISO 32000-1).