You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you today?

USER: I want to change my existing reservation, due to my trip has been postponed. Can you please aid me to change it?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know your name to proceed further?

USER: Sure, my name is John Allen.

ASSISTANT: Please wait for a while, let me check me with the reservation status and get back to you.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no active reservation found on your name to change.

USER: Ok, no problem. Thanks for your help.

ASSISTANT: Thank you for availing us.