Expense Report email notification

We are using ebs version 12.1.3

One of the manager is getting emails asking him to approve a expense report. And later on he gets another email notification saying that the notification has been cancelled on the previous one and he does not have to respond, but delete the email. Looks like he should just delete and ignore the emails. But, I am not sure if this could be due the some error that he got these email? If there a way to verify whether he can truly ignore those emails? Gurus, please advise. Thank you very much.