You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I be of your service?

USER: I am Rachel Carter, I want to change my reservation as my plan to visit my friend is postponed. Can you help me with that?

ASSISTANT: Sure,please let me know your name for change an existing reservation.

USER: Rachel Carter.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, we did not found any reservation by this name. Thanks for opting us.

USER: Ok, thanks for the information.