You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, may I know your name for the changing process?

USER: My previous reservation has done with my name Larry Thompson.

ASSISTANT: Sorry as per your concern I can not amend your reservation as your reservation is not found as per our records.

USER: Ok, not an issue.

ASSISTANT: Welcome, thank you for reaching us.

USER: Thank you for providing information.