You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Can you please change my details in my existing reservation?

ASSISTANT: Sure, will you provide the name for checking your reservation?

USER: I have reserved my ticket in the name of Dennis Roberts.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: Thank you for waiting. There is no reservation found under your name.

USER: Ok, fine thank you for informing me.