Let's consider next example: 
Person can send StartFinalExam cmd and SubmitFinalExam cmd. There are FinalExamStarted evt and FinalExamGraduated evt.
Course handle StartFinalExam cmd and generate FinalExamStarted event. It also handle SubmitFinalExam cmd and generate FinalExamGraduated event.
FinalExamGraduating Saga starts on FinalExamStarted. It ends on FinalExamGraduated. If FinalExamStarted didn't come during 1 hour after FinalExamStarted it should generate SubmitFinalExam(0) event.