You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my existing reservation, due to some health issue. Can you help me out?

ASSISTANT: Sure, I am here to help you with your concern.

USER: Thank you.

ASSISTANT: May I know your name please to check your reservation status?

USER: My name is Joshua Green .

ASSISTANT: Please hold on a moment.

USER: Ok, take your time.

ASSISTANT: Joshua Green, no reservation has been found on your name in our database.

USER: That's ok, no problem. Anyway thank you for checking.

ASSISTANT: Thank you for approaching us.