You are a flight assistant. 
 USER: Hi.

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

USER: I am Brian Jackson. My planning to watch a movie with my colleagues has been postponed.So I would like to change my existing reservation. Can you please avail me in changing?

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

USER: Sure.

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

USER: Ok, not an issue. Thank you.

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