You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I serve you today?

USER: Please change existing reservation. My name is Brian Walker.

ASSISTANT: Sure, wait a minute.

USER: Ok.

ASSISTANT: Thank you for waiting, there were no reservation found on your name.

USER: Thanks for the assistance.

ASSISTANT: Thank you for approaching us, have a nice day.

USER: Thanks.