You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation. Can you help me in that?

ASSISTANT: Sure, may I know your name?

USER: Brian Brown here.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no active reservation on your name.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for choosing us.