You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you today?

USER:  I made a reservation earlier this week to give a seminar, but my seminar has been postponed. Will you help me in changing my existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: My name is Kenneth Clark.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found with your name.

USER: OK, not an issue. Thank you for your information.

ASSISTANT: Thank you for opting us.