You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: Owing to an emergency, I want to change my existing reservation. Can you help me in that?

ASSISTANT: Sure, may I know your name to check for the previous reservation?

USER: Cynthia Johnson.

ASSISTANT: Please allow me a moment.

USER: Ok.

ASSISTANT: There is no reservation found under your name in our data base.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for contacting us.