You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Ryan Miller.

ASSISTANT: Ryan Miller. How can I help you?

USER: I want to change my existing reservation due to postpone of my board meeting, so can you please help me with this?

ASSISTANT: Sure, I will help you with that. Can you give me a moment?

USER: Sure.

ASSISTANT: I regret to inform that there is no reservation by the name Ryan Miller.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for reaching us.