You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Richard Williams, want to alter my recent reservation due to some personal issue. Please help me out with that..

ASSISTANT: Sure, I will help you with the change of flight reservation.

USER: Thanks.

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

USER: It's ok, thank you for your help.

ASSISTANT: Thank you.