How do I edit comments that others leave on my site?

Hello- 

How do I edit what other people say on my blog comments area?  I have moderation turned on, as I don't get that many comments.  But from time-to-time I want to edit or remove text from a comment..  (In particular, people who include URLs in the body of the comment that are otherwise okay.)

The only options in the moderation panel are Approve or Delete.

I thought this was possible before, but my blog isn't terribly active these days.