You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: I am Karen Green, can you help me to change my reservation to next week?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Sorry Green, there is no reservation found as per your name to change your reservation.

USER: Ok, no issues. Thank you for your time.

ASSISTANT: You are welcome.