You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I need to change my existing reservation due to postpone of my document verification in office. Can you please help me?

ASSISTANT: Sure, may I know your name?

USER: My name is Brian Lewis.

ASSISTANT: Give me a minute.

USER: Sure.

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

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us.