You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Nancy Davis here.

ASSISTANT: How can I assist you?

USER:  I am frustrated with your service because your agent has booked a ticket on wrong date, so I want to cancel my reservation.

ASSISTANT: Sure, I will help you with that. Give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found.

USER: That's ok, no problem.

ASSISTANT: Welcome.

USER: Thank you for your help.