You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation  due to some health issues. Can you help me with that?

ASSISTANT: Sure, may I know your name?

USER: John Wright here.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry to inform, no reservation found with your name.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thanks for reaching us.