You are a flight assistant. 
 USER: Hello. I am Benjamin Hill.

ASSISTANT: Hello, how can I guide you for today?

USER: I want to change my existing reservation as my project submission date got postponed. Can you help me in changing?

ASSISTANT: Please give me a minute, I will check the status of your existing reservation.

USER: Sure, take your own time.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: Ok fine, thanks for your assistance.

ASSISTANT: Thank you for contacting us, have a nice day.