You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I need to change my existing reservation, can you please help me in this issue.

ASSISTANT: Sure, may I know your name to check for the previous reservation?

USER: Myself Robert Adams.

ASSISTANT: Please allow me a moment.

USER: Please take your time.

ASSISTANT: Robert, there is no reservation found under your name.

USER: Not an issue, thank you for searching the details.

ASSISTANT: You are welcome.