You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I address you?

USER: Please change my existing reservation due to some health issues?

ASSISTANT: Sure, will you please let me know your name?

USER: Sure, I am Daniel Taylor.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, I have gone through the reservation list but could not find any reservation active under your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.