You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: Sure, may I know your name?

USER: Daniel Jackson.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thanks for your information.