You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Please help me in changing my existing reservation details.

ASSISTANT: Sure, I can help you before that, can I have your name so that I can help you easily.

USER: Sure, my name is Brenda Rodriguez.

ASSISTANT: Thanks for your giving your name, please wait a moment.

USER: Ok.

ASSISTANT: Thanks for your time, there is no reservation with your name.

USER: It's ok, thank you for the information.

ASSISTANT: Ok, thanks for choosing us.