You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Helen Moore here.

ASSISTANT: How may I aid you?

USER: Can you please help me in changing my recent reservation? As my planned trip has been postponed.

ASSISTANT: Sure, I am here to help you. Please wait a moment.

USER: Sure.

ASSISTANT: Helen, no reservation has been found on your name in our database.

USER: That's ok, thank you for giving the information.

ASSISTANT: Thank you for approaching us.