You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Elizabeth Brown here.

ASSISTANT: How can I assist you now?

USER: Due to urgent work in my office, I want to alter my reservation dates. Can you alter my reservation?

ASSISTANT: Sure, I will help you with that.

USER: Ok.

ASSISTANT: Please be hold on for a moment.

USER: Sure.

ASSISTANT: Sorry Brown, there is no reservation found under your name.

USER: It's ok.

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

USER: Thanks.