I presume that change order is approved if all task are approved, and rejected when any task is rejected. For simplicity you can update change status to cancelled when any task is rejected, since this will cancel any active or waiting task.
So in this case You can try to built the following workflow.
group start task
approval task 1 (does nothing if approved, set change status to canceled if rejected)
approval task 2 (does nothing if approved, set change status to canceled if rejected)
approval task 3 (does nothing if approved, set change status to canceled if rejected)
approval task 4 (does nothing if approved, set change status to canceled if rejected)
group end task (changes change status to approved if change status not equal to cancelled)