You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Owing to emergency, I need to change my recent reservation. Please help me with that.

ASSISTANT: Sure, can I know your name?

USER: I am John Smith.

ASSISTANT: Please hold on a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on given name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.