You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Myself Elizabeth Wright. I am going to change my existing reservation. Can you please help me for this?

ASSISTANT: Sure.

USER: Ok, I will wait for your response.

ASSISTANT: Wait for a moment please. I will check and get back to you.

USER: Sure.

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 problem, anyhow thank you very much for your service.

ASSISTANT: Thank you.

USER: You are welcome.