You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, will you mention your name for checking the reservation status?

USER: I am Brenda Wilson.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found under your name.

USER: Oh! That's fine. Thank you for checking.

ASSISTANT: Welcome, have a great day.

USER: Most welcome.