You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: By mistake I have booked a flight for round trip so, can you please change my existing reservation to New York airport?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: May I know your name to check your details in our reservation list?

USER: Mark King is my name.

ASSISTANT: Ok, give me sometime to check and I will revert to you with the current status.

USER: OK.

ASSISTANT: Thank you for your valuable time, we are sorry to inform you that there is no reservation found on your name to do modifications.

USER: Ok, that's not a problem. Leave it. Thanks for your quick response.

ASSISTANT: Thank you for consulting us.