From Bright Pattern Documentation
Removing Users from Reports
My reports show employees who no longer work with us. How do I delete the inactive users and their profiles?
Currently we do not have functionality that will allow you to remove data from old users. As your reports become more current, these agents will not appear in your reports.
Data is maintained for agents after they have been deleted, until the "age off" period for your data (historical detailed and aggregated). As this data ages, the agents who had been deleted would be removed. Some tenants keep their settings at 1 year for storing detailed records and 2 years for storing aggregated records. You may not wish to lessen this amount of time any further, as all reporting would be lost, not just the deleted agents.