You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation due to postpone of my seminar. Could you please help me?

ASSISTANT: Sure, may I know your name please?

USER: I am Kenneth Hernandez.

ASSISTANT: Wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no reservation found for the user name in our data base to change your previous booking.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for opting us.