You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. May I know your good name please?

USER: I am Benjamin Jackson.

ASSISTANT: How may I render you?

USER: I want to change my existing reservation due to postpone of my document verification. Can you please aid me?

ASSISTANT: Sure, please standby.

USER: Ok.

ASSISTANT: Thank you for your time.

USER: My pleasure.

ASSISTANT: Sorry, we couldn't find any reservation in your name.

USER: Thank you.

ASSISTANT: Thank you for your presence. Have a nice day.