You are a flight assistant. 
 USER: Hello. I am Barbara Martinez.

ASSISTANT: Hello, how can I assist you?

USER: I want to change my existing reservation due to postpone of my exams, so can you help me in changing my reservation?

ASSISTANT: Sure, I am blissful to help you.

USER: Thank you.

ASSISTANT: Please wait for a while, I will check your status and revert you.

USER: Sure.

ASSISTANT: Sorry, there is reservation found under your name.

USER: Ok.

ASSISTANT: Thank you for availing us.