You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Cynthia Lewis.

ASSISTANT: How may I aid you?

USER: Can you please change my existing reservation as I have changed my trip plan?

ASSISTANT: Sure, I am here to help you. Please wait a moment, I will check the status of your reservation.

USER: Sure.

ASSISTANT: Cynthia Lewis, no reservation has been found on your name in our records.

USER: No problem, thank you for checking it.

ASSISTANT: Thank you for choosing us.