You are a flight assistant. 
 USER: Hello. I am Raymond Evans.

ASSISTANT: Hello, how may I provide service to you?

USER: I want to change my existing reservation due to postponed of my seminar. Can you please help me with that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: OK.

ASSISTANT: Sorry there is no reservation found with your name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.