You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am Brenda Williams, can you please help me with change my existing reservation which was reserved last week?

ASSISTANT: Sure, please wait for a few minutes.

USER: Ok.

ASSISTANT: Thanks for your time, no reservation was found on your name.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for choosing us.