You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you?

USER: Myself Jack Williams, due to some urgent seminars. I am going to change reservation. Can you please help me in changing the reservation?

ASSISTANT: Sure, I will help you in change of flight reservation. Please wait for a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Thanks for waiting. But I am sorry to say that there is no flight reservation on your name to change it.

USER: Not a big deal, anyhow thank you very much for your service.

ASSISTANT: Thank you.