title: c#.net Regex - Need to find a sequence of characters, then replace one character within it
body: <p>I'm trying to build a regex that can look for names that contain apostrophes (O'Connor, O'Neil) and replace the apostrophes with 2 apostrophes (O''Connor, O''Neil).</p>
  
  <p>I don't want to do this with all apostrophes in the string in question, just apostrophes that appear between two letters (upper or lower case). Now, I have no trouble finding instances of LETTER-APOSTROPHE-LETTER, but I'm not sure how to take that sequence and change the <code>'</code> to <code>''</code>.</p>