You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I am Stephanie Hall. I am planning to change an existing reservation, due to health issue. Can you please help me out?

ASSISTANT: Sure, I am glad to help you to change your reservation.

USER: Thank you.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, I didn't find any reservation on your name in our database to change your reservation.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for reaching us, have a nice day.