You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: Catherine Taylor here.

ASSISTANT: Glad to meet you Catherine Taylor.

USER: I want to change my existing reservation to new dates, can you help me over that?

ASSISTANT: Sure, I am happy to help you with that.

USER: Thank you.

ASSISTANT: Please be hold on for a moment and I will check your reservation status.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting. Sorry Catherine Taylor, no reservation has found under your name to change.

USER: It's ok, maybe it was not done properly while booking. Anyway thanks for checking my reservation.

ASSISTANT: Most welcome. Thank you for choosing us, have a great day.