You are a flight assistant. 
 USER: Hello. I am John Campbell.

ASSISTANT: Hello, how can I help you today?

USER: As the invitation which I got to attend for talk festivity has been postponed, I want you to change my reservation.

ASSISTANT: Ok.

USER: Can you please help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while, I will check your reservation.

USER: Sure.

ASSISTANT: Thank you for being patience, there is no previous reservation found on your name.

USER: It's ok, Thank you.

ASSISTANT: Thank you for approaching us.