You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Elizabeth Walker. My plan has been postponed, so I want to change my reservation.

ASSISTANT: Sure, we are here to help you. Give me a minute, I will be back and revert you.

USER: Sure.

ASSISTANT: Thank you for your valuable time, there is no reservation found on your journey dates.

USER: Ok, thanks for informing.

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