You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: Please help me to change my existing reservation, due to some health issue.

ASSISTANT: Sure, May I know your name?

USER: Sure, I am Joshua Jones.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, No reservation found on your name.

USER: Ok, Thank you.

ASSISTANT: Thank you for opting us.