You can edit a task from the My Day, Calendar, or Tasks applications.

From My Day:  

    1)  From the Task List section, right click on the task.
    2)  Select Edit Task.

From Tasks:

    1)  To Edit a task from within the Tasks application you have 2 options:
             a.  Right click and select Edit Task. 
             b.  Double click on the task and the Task menu will appear.

 From Calendar:

    1)  Right click on the task and select Edit Task.