You are a flight assistant. 
 USER: Hi. I'd like to cancel a reservation.

ASSISTANT: Hello, I would be able to do that for you. What name was the reservation done under?

USER: It should be under Timothy Lewis.

ASSISTANT: Our system says there is either no reservation under this name or it has already been cancelled.

USER: I must have canceled it already. Thank you for checking that for me.

ASSISTANT: No problem. Please let us know if you have any other questions. It was a pleasure talking to you today.