Once your paragraph has been recorded in the story tree, you
can still change it later on. If you've just read one of your
paragraphs and decide you want to change it, say "edit". That
puts me into writing mode for that one paragraph. It also
puts you at the END of the paragraph. That means that any lines
you say will be added on to the paragraph, unless you delete
some lines first or wipe the whole paragraph and start over
by saying "clear". Once you finish the paragraph, I come back
out of writing mode.