You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER: I am Angela Adams. I want to change my reservation.

ASSISTANT: Sure, I am happy to help you with that.

USER: Thank you.

ASSISTANT: Sorry Adams, no reservation found on your name in our database. I think your previous reservation not done before.

USER: That's ok. Thank you.

ASSISTANT: Thank you for approaching us.