You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I want to change my reservation, can you help me?

ASSISTANT: How may I help you? Sure, I am happy to help you. Can I know your name?

USER: Myself Brenda Roberts.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.