You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Larry Brown.

ASSISTANT: How may I assist you today?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait a minute.

USER: Ok, take your time.

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

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

ASSISTANT: Thank you for choosing us.