You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Can you aid me to change my reservation due to emergency?

ASSISTANT: Sure, I am here to help you with that, can I know your good name to proceed further?

USER: David Moore here.

ASSISTANT:  I am very sorry to inform you that there is no reservation found under your name in our database.

USER: Thank you for the help.

ASSISTANT: Thank you for choosing us.