You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: Can I know your name?

USER: I am Linda Nelson.

ASSISTANT: Sorry, no reservation found by your name.

USER: Ok, no problem.

ASSISTANT: Thank you.

USER: Thank you for your information.