Exchange Server users can assign tasks to others and receive status updates as users work on and complete the tasks. However, the user who assigns the task can't be the one who works on the assigned task.
In some situations, it's helpful for users to keep a copy of an assigned task so they can work on it along with the assignee. To work on an assigned task, the user must create an unassigned copy in his or her own Tasks folder.
Follow these steps:
Outlook creates the task in the Task folder, replacing the original assigned task. The subject changes to include the word "copy." Users can then work on the task as they would any other.
Again, if you create an unassigned copy for yourself, you'll no longer receive updates for the assigned task. But in some situations, the ability to work on an assigned task outweighs this disadvantage.