You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Brian Hill.

ASSISTANT: How can I help you?

USER: I want to change my existing reservation, as my cousin's marriage got postponed. Can you please help me with this?

ASSISTANT: Sure, I will help you out. Just a moment please.

USER: Sure, take your time.

ASSISTANT: I am sorry no reservation found on your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.