You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Can you aid me in changing my recent reservation, which I had done before?

ASSISTANT: Sure, I am here to help you. May I know your name please?

USER: Myself Sarah Martinez.

ASSISTANT: Ok, please wait for a moment.

USER: Sure, take your time.

ASSISTANT: Sorry Sarah, there is no reservation found on your name to change it.

USER: That's ok, thank you for checking.