You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I need to change my existing reservation owing to an emergency.

ASSISTANT: Sure, I am here to help you. Can I know your name?

USER: My name is Christopher Jackson.

ASSISTANT: Thank you. I will check your reservation status and let you know.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: Thank you.

ASSISTANT: You are most welcome.