You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Debra Davis.

ASSISTANT: How can I assist you?

USER: Can you please change my existing reservation as my plan to attend a seminar got postponed?

ASSISTANT: Sure Davis, please wait a moment.

USER: Sure, I will wait.

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

USER: It's ok, no problem.

ASSISTANT: Thank you for approaching us.

USER: Thank you for the information.