There are fairly frequent complaints here about the inability of readers to preview their comments before they’re posted. I sympathize with this (I’m exempt, of course, because I can edit my own posts and comments), but I’m sorry to say that this stricture is not my own: WordPress simply doesn’t allow readers the option of previews or post-comment editing.
That said, I can edit readers’ comments. if you’ve made some egregious error, forgotten to close your italics using HTML tags, or wish to make an important change in something you’ve said, just shoot me an email (you can find my work email simply by Googling my name and the name of my university) and ask me to make the change. I’ll be glad to accommodate, and have done so a fair number of times.