Board Thread:Support Requests - Community Management/@comment-5891886-20141002040019/@comment-4241794-20141002040602

You have to go on the page you want to do that to and go to the edit button. Next to it will be a little arrow, click on that and then hit Change Protection, and set it to "Block new and unregistered users". Then they can't edit that page but they can still look at it, make pages, and comment.