You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hi,.

USER: I am Samantha Mitchell.

ASSISTANT: Hi,. How may I help you?

USER: I want to change my existing reservation from New York to Seattle.

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

USER: OK, Thanks for your information.

ASSISTANT: Thank you, Have a nice day.