You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Brian Baker.

ASSISTANT: How may I assist you?

USER: I just need your help in changing my existing reservation details.

ASSISTANT: Sure, I will help you.

USER: Ok.

ASSISTANT: Sorry Baker, no reservation has been found on your name in our database.

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

ASSISTANT: Thank you for approaching us.