To delete a task, perform the following steps:
Tap Tasks from the calendar toolbar.
A list of tasks is displayed with a minimal set of attributes. If
your task does not appear on the list, you can search your tasks by
typing the search attributes in the search text field. To know more
about how to Search Tasks, see How Do I Search for a Task from My Calendar?
Tap the delete icon located to the right of the task, under the Status column.
A dialog box appears prompting for a confirmation on the delete action.
Tap Delete.
The task is deleted from the calendar.