There's no quick and easy method that I know of. Although I'm
a big fan of the FAR utility, trying to remove opening and closing
tags without being sure of the content between them might be
problematic, if not downright impossible.
An alternative might be what I'll call the "slash-and-burn"
method:
1. In RH WYSIWYG mode select and cut the entire topic
(Ctrl+A, Ctrl+X).
2. Paste the content into Notepad (
not MS Word), select all and copy (Ctrl+A, Ctrl+C).
3. In RH WYSIWYG mode paste the content from step 2 (Ctrl+V).
4. Apply your styles.
A caveat: don't use styles for bullet/number lists,
especially if you'll be producing Printed Doc output at some point.
Rh works best if you just select the list items and click the list
icons in the RH toolbar.
I know this method might seem daunting, but I've been there,
done that. Give yourself a few days, put your head down, and just
do it.
Good luck,
Leon