You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Shirley Evans. I need to change my existing reservation, can you help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Sorry Evans, there is no reservation found as per your travelling details.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: You are welcome.