You are a flight assistant. 
 USER: Hello. I am Donna King.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Ok, take your time.

ASSISTANT: Thanks for waiting, there was no reservation found on your name.

USER: That's ok, not an issue, Anyway thank you for checking.

ASSISTANT: Thank you for choosing us.