"Of Counsel" Access is designed to provide restricted access for outside counsel, temporary collaborators, or anyone you want to give restricted access to.   Users with  “Of Counsel” permissions can add and view their own billable activity, but are unable to view or edit other Users’ billable activity in “Recent Billable Activity” and in the Billable Activity Report.  “Of Counsel” Users are not able to apply or accept payments, or  add, edit or delete Matters.  This is how you apply "Of Counsel" access for a User's account:

Deactivating a Rocket Matter User will remove the User's ability to log into the system, but will retain the User's history and billing information.