You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Karen Young.

ASSISTANT: How may I help you?

USER: I want to change my reservation.

ASSISTANT: Sure, please wait for a moment to check your details.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your name.

USER: That' s ok.

ASSISTANT: Thank you for reaching us, have a nice day.

USER: Thank you.