You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

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

ASSISTANT:  Sure, I am here to help you. May I know your name to check with existing reservation?

USER: Rebecca Adams here.

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

USER: Thank you.

ASSISTANT: Thank you for choosing us.