You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Carol Williams,I accidentally booked a ticket on wrong dates, would you help me in changing the reservation?

ASSISTANT: Sure Williams, give me a moment.

USER: OK.

ASSISTANT: Let me check your details. I am sorry Williams, I didn't find any reservation basing on your details.

USER: OK, thank you for providing me information.

ASSISTANT: Your welcome.