You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Daniel Brown.

ASSISTANT: How can I help you Brown?

USER: I need to change my existing reservation, can you please help me with that?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your name.

USER: Ok, no problem.

ASSISTANT: Thank you for approaching us.

USER: Thanks for your information.