You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you at this moment?

USER: I want to change my existing reservation due to sudden postpone of my trip dates. Can you help me with that?

ASSISTANT: Sure, I will help you with that. May I know your name for further process?

USER: Thank you.

ASSISTANT: Ok, please hold on a moment.

USER: I am Samuel Hill. Sure.

ASSISTANT: Thank you for providing details, please wait a moment.

USER: Ok.

ASSISTANT: There is no previous reservation available under your name.

USER: Ok, no problem. Thank you for your response.

ASSISTANT: Thank you for reaching us.