Posts can be edited by clicking the cogwheel next to the discussion:
Permissions for editing can be controlled by posting settings, by rank, or by role.
From the Posting Settings : Located in the Discussions setting of your dashboard, Discussion and Comment Editing allows Community Manager to set the window for which authors are allowed to edit their own post.
By rank, via the user's rank abilities (when editing a rank then scrolling down to abilities). These settings will supersede what is set in the Posting Settings.
By role : Allowing users to edit all content in a category. This is designed for Moderators and Community Managers.
For more information read up in the Roles and Permissions article.
A Moderator or Administrator can access Revision History by loading the post menu. Editing posts will also include a time stamp to describe when the post was edited. Clicking on Revision History from the post menu will direct the user to the change log.
This is designed to replace our Legacy add on Last Edited which adds a label to the bottom of post describing the time of edit and a link to the change log.
How do I know if a post has been edited?
You will see this in the metadata:
How do I know who made the edit, and what they changed?
By navigating to the Dashboard, then Moderation, then Change Log:
You can choose to restore the previous version by clicking the checkbox next to the edit and then hitting 'restore'