You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Yesterday I booked a ticket to New York through your agency, your agent by mistakenly booked a ticket on wrong dates, so I want to cancel my reservation.

ASSISTANT: Please wait for a moment, let me check your details.

USER: Ok, sure.

ASSISTANT: Can I know your name?

USER: I am William Taylor.

ASSISTANT: Sorry Taylor, there is no reservation found with your details.

USER: Oh! ok, thank you for the information.

ASSISTANT: Most welcome.