You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Nancy Taylor.

ASSISTANT: How may I aid you?

USER: Due to some meetings I am going to change my existing reservation. Can you please help me for changing the reservation?

ASSISTANT: Sure, I am here to help you out.

USER: Ok. I will wait for your response.

ASSISTANT: Sorry to say you that, there is no flight reserved on your name in our database.

USER: Not a big problem, anyhow thank you very much for your help.

ASSISTANT: Thank you for reaching us.