You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: Sure, I am Stephanie Carter.

ASSISTANT: There is no reservation found under your name.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing us.