You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I serve you?

USER: Help me in changing my reservation?

ASSISTANT: Sure. Tell me your name please?

USER: I am Catherine Taylor.

ASSISTANT: Please wait.

USER: Ok.

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

USER: That's ok, thank you.

ASSISTANT: Thank you.