You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Christine Campbell.

ASSISTANT: How can I help you today?

USER: I want to do some modifications in my previous reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, I will help you for to change your reservation.

USER: Thank you.

ASSISTANT: Please give me a moment to check your previous reservation.

USER: Ok, take your time.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: That's ok, no problem. Anyway thank you for checking.

ASSISTANT: Welcome. Have a nice day.