You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Mary Smith.

ASSISTANT: How may I assist you?

USER: I want to change my reservation as I want to stay for some more days at Seattle, can you please do that for me?

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

USER: Thank you so much.

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

USER: Not an issue. Anyway, thank you for checking.

ASSISTANT: Thank you.