You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my existing reservation due to my health issue, can you please help?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I know your name to change your reservation?

USER: Sure, my name is Larry Phillips.

ASSISTANT: Sorry, there is no reservation on your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you.