How to cancel a task?
No task can be completely erased from the ProgressionLIVE database, but tasks can be cancelled.
Once a task is cancelled, it is no longer visible to the users.
Since nothing is really erased in ProgressionLIVE, it is possible to see cancelled tasks by clicking on the gear icon at top right and checking Show cancelled tasks.
Make sure the task filter on the left matches the time period your canceled tasks are in so you can see them.