Changes you make to reviews in Reva do not appear on your website immediately. They appear after the next scheduled sync.
How the sync works. Your website checks Reva on a scheduled interval that is set per site, for example every 10 hours. At each run, it pulls in reviews that were added or changed in Reva over the last two days.
Publishing a review. A review you publish in Reva appears on your website at the next scheduled run.
Unpublishing a review. A review you stop publishing in Reva is removed from your website at the next scheduled run, provided you are running the current version of the Reva review plugin. Older versions of the plugin only add reviews and do not process unpublish actions.