You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I need to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: Sure, I will assist you with that. May I know your name for further process?

USER: Sure, my name is Brenda Lopez.

ASSISTANT: There is no previous reservation available under your name.

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

ASSISTANT: You are welcome Brenda Lopez.

USER: Thank you for searching.