How to change the font size of a single character?

Hello,

  I was wondering if someone could tell what I need to do to change
  the font size of a single character within a paragraph:

  <para>
      I want the letter 'A' to be 24 pt. within the word want.
  </para>

  what do I need to do to make this work?

  thanks to anyone who can help!!

  mike