You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Robert Perez.

ASSISTANT: What can I do for you today?

USER: I want to change my  reservation due to postpone of my bussiness meeting at New York. Can you help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for few minutes, I will check with your existing reservation status.

USER: Ok.

ASSISTANT: There is no existing reservation found on your name in our data base for the modification.

USER: Ok, thank you for informing me.

ASSISTANT: Thank you for availing us.