You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

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

ASSISTANT: I will help you with that. May I know your name?

USER: My name is Katherine Miller.

ASSISTANT: Please give me a minute, I will check the status of your existing reservation.

USER: Ok, I will wait for your response.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

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

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