Insufficient privileges on an update join
update (select grw.approver_user_id, gup.supervisor_id
        from   gs3.user_role gur
          join gsu.user_profile gup
            on gur.user_id = gup.user_id
          join gs3.request_workflow grw
            on gur.user_role_id = grw.user_role_id
           and gup.supervisor_id != grw.approver_user_id  -- records with new mgr
        where  grw.auth_status_cd = 'SUBMITTED')  -- reapprovals currently open
set    grw.approver_id = gup.supervisor_id;

Update gs3.request_workflow
Set approver_id =   (
                    Select gup.supervisor_id
                    From gs3.user_role As gur
                        Join gsu.user_profile As gup
                            On gur.user_id = gup.user_id
                    Where gup.user_role_id = gs3.request_workflow.user_role_id
                        And gup.supervisor_id != grw.approver_user_id
                    )
Where auth_status_cd = 'SUBMITTED'
    And Exists  (
                Select 1
                From gs3.user_role As gur
                    Join gsu.user_profile As gup
                        On gur.user_id = gup.user_id
                Where gup.user_role_id = gs3.request_workflow.user_role_id
                    And gup.supervisor_id != grw.approver_user_id
                )