You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Sarah Miller. I need to change my recent reservation due to postpone of my brother's engagement. Could you please help me in doing that?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: Sorry to say, no reservation found with your name.

USER: Fine, thank you for your information.

ASSISTANT: Thanks for reaching us.