The ability to edit closed tickets has been a long popular and long requested enhancement. The Modify Closed Tickets beta is the first step in adding this functionality. With this beta, we will be initially providing the ability for administrators to update tags on closed tickets. This community will serve as a place to provide feedback on the first foray into this workflow as well as provide a place to share your thoughts on how we should expand this feature in the future.
With the beta now live, you can find help about how to use this functionality via this help document.