You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I would like to change my recent reservation because my health condition was not good, can you help me?

ASSISTANT: Sure, I am here to help you. May I know your name?

USER: I am Joseph Lewis.

ASSISTANT: Sorry, there are no reservation found on your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.