You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: Could you please change my existing reservation?

ASSISTANT: Sure, we are happy to help you. Please let me know your good name.

USER: I am Helen Lopez.

ASSISTANT: Sorry, there is no active reservation on your name in our records.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for choosing us.