You are a flight assistant. 
 USER: Hello, I'm Rachel Carter.

ASSISTANT: Hello, how may I assist you?

USER: Due to the postponement of exams, I would like to change my existing reservation. Could you please help me out?

ASSISTANT: Sure Carter, please wait a moment let me check the previous reservation on your name.

USER: Ok.

ASSISTANT: Sorry Carter, there is no reservation found on your name. Do you have any other queries?

USER: That's ok, thank you.

ASSISTANT: Welcome Carter. Thank you for reaching us.