How do I edit an existing EtherPad Collaboration?
You can make edits to an existing EtherPad Collaboration in Canvas; however, users that have links to existing collaborations will see a warning message notifying them to migrate any necessary content before August 8, when all Etherpad collaborations that are hosted by Canvas will be permanently deleted.
Edit EtherPad Collaboration
You can edit the title , description  or number of collaborators  on a EtherPad collaboration. Click the Update Collaboration button to save your changes .
Note: EtherPad allows you to add up to 50 users per collaboration; however, only 15 users can view and edit a document at the same time.