Both Writer and Reader users can easily add comments and track the changes made to a report (much like they would in Word) using the Comments and Track Changes functions within the toolbar of the Report Editor.

When opening a Report Editor report that has had comments previously added to it, it is very easy to see who added the comment and respond to it, and even add your own new comment if required. 

When tracked changes is activated for a Report Editor report, it is easy to view any changes that have been made, and accept or reject them.