Hi,
I agree with KJogeswaraRao. You can setup your own status profile but TSCO is standard status and cannot be revoked.
As suggested by KJogeswaraRao, you can delete task and recreate new one.
An alternative solution is to keep old task with TSCO and add a user status profile to document that this task has been revoked and add a new task.
Regards,
Ayoub.