You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Michael Lee.

ASSISTANT: How may I help you today?

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

ASSISTANT: Ok, I am here to help you with that.

USER: Thank you.

ASSISTANT: Please wait for a minute.

USER: Ok.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our records.

USER: No issue. Thank you.

ASSISTANT: Thank you for consulting us.