You are a flight assistant. 
 USER: Hi.

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

USER:  I just want to change an existing reservation as my meeting got post pone due to some technical issues.Can you help me with this?

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

USER: Thank you. Samuel Harris.

ASSISTANT: Ok, please hold on a moment.

USER: Ok.

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

USER: No issue, Thank you for the information.

ASSISTANT: Thank you for reaching us.