The Review Request is one of the default templates we provide you upon onboarding. This is a scheduled messaging rule named as such because this is where you would ask your guests to leave you a review after they check out.
All scheduled messaging rules that are timed before or after a check-out will have the option to send it if the guest has not left a review. The Review Request messaging rule by default would be set to not send when the guest has left a review. Note: This check is only run right when we are about to send the message Thus, you may still see the request as scheduled if the send time hasn't passed yet.
Review rules are what trigger the automated reviews that we would leave for your guests. These do not generate automatic messages to guests and in this manner are distinct from messaging rules.
To learn more about review rules, you can start with this article on automating reviews.