You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Sarah Turner.

ASSISTANT: How can I assist you at this moment?

USER: I am planning to change an existing reservation, due to health issue. Can you please change my reservation?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please be hold on for a moment to check your reservation status.

USER: Sure, take your own time.

ASSISTANT: Sorry Sarah Turner, no reservation has found under your name to change.

USER: That's fine. Thank you for your help.

ASSISTANT: Most welcome. Thank you for choosing us, have a great day.