A user contacted me with a problem:
When I go to File, Options, Stationery and Fonts in Outlook, the buttons to change fonts are greyed out. How do I fix this?
It sounds like you are using a default theme for your email. When a theme is assigned, you have three choices for the font: Use theme's font, Use my font when replying and forwarding messages, and Always use my font.
When Use theme's font is selected, the buttons to change the font will be disabled. Choose Always use my font to enable both Font… buttons or Use my font when replying… to enable the Font button for Replies and Forwards.