You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am John Green. Previously I have made a flight ticket booking and due to some reasons the trip got postponed, can you please help me in flight ticket modification process?

ASSISTANT: Sure, please wait for a while.

USER: Thank you for accepting my request in positive manner and I can wait for your response.

ASSISTANT: Sorry, there was no reservation found with your given name.

USER: Ok, no problem with that one. I think it is not booked properly while I was booking. Thank you for your information.

ASSISTANT: Thank you for opting us.

USER: Welcome.