Once the review appears on the New Reviews page, click on the "View" button beside the provider's name. This will take you to the provider's profile screen. Click on the "Report a Problem" link (above the General Information section). This opens a new window containing a box where you can type in the update.
That's true...I guess I read the question in terms of general info changes (to the provider's profile). If you actually wanted to change details from a specific review, I imagine that that would require a closer look before the changes were approved.