You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what help are you seeking from our side?

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

ASSISTANT: Ok, may I know your name to check with your previous booking?

USER: Sure, my name is Nancy Young.

ASSISTANT: Sorry to say, there is no flight reservation available by your name.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for choosing us Nancy Young.