You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Sure, give me a minute.

USER: Ok, take your time.

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

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

ASSISTANT: Thank you for reaching us.