if you're certain that there's no existing tasks for those records, then you may be safe to adjust the lines in the database (this advice is given with the usual "manual database adjustment" disclaimer - at own risk and the sort).
Anyways, I believe these are the only fields you need to adjust in your ProcessManager database.
--ReportProcess.Result = 'Closed'
--ReportProcess.PercentComplete = '100'
--ReportProcess.ProcessEnded = getdate()
--IMIncidentTicket.CloseCode = 'Closed'
--IMIncidentTicket.TicketStatus = 'Closed'