You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I want to change my existing reservation due to some business meeting postponed, can you please help me out?

ASSISTANT: Sure, may I know your name to check your status?

USER: Ok, my name is Rebecca Phillips.

ASSISTANT: Ok, please wait a moment.

USER: Sure, take your time.

ASSISTANT: There is no reservation found under your name to change your reservation.

USER: Ok, that's fine.

ASSISTANT: Thanks for consulting us Rebecca Phillips.

USER: Thank you for your valuable time.