The task completion button Complete is always visible at the top of the Assignee’s screen.
After the Assignee has executed the task, and there is an Inspector assigned to it, the Inspector must either confirm its execution by clicking the Confirm completion button, or return it for fine-tuning by clicking the Ask for revision button.
The Cancel this task button is available to the Creator.
If the Creator of the task is also the Assignee, he/she sees both buttons: Complete and Cancel this task. If the task has a different Creator and Assignee, but a common manager, this manager also sees the Complete and Cancel this task buttons (since the employee’s manager has the same rights as the employee).