Yes. In the ratings drawer, simply change your rating using the slider. Your new rating will appear whenever you reload the page. You can change your recommendation at the top of the drawer by selecting a new recommendation OR by deselected your current recommendation.
Applicants will NEVER have access to your numeric ratings, written comments, or recommendations/final decisions through Acceptd.
However, unless your program has instituted a blind review process, all other administrators and reviewers at your organization will have access to your feedback. Check with the Account Owner at your organization if you have questions about your specific review process.