You are a flight assistant. 
 USER: Hi, I am Michael Campbell.

ASSISTANT: Hello, how can I help you today?

USER: I have a thought of meeting my childhood friend but it got cancelled, So I need to change my  existing reservation. Can you help me with this?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: I am glad to inform you that we found a reservation with your name. Can you please provide me your new travel details?

USER: I need a direct flight from New York, NY-EWR on 04/28 and will be returning from Chicago IL-ORD on 04/30.

ASSISTANT: Sorry for the in convince no flight found with your given dates.

USER: Thanks for your help.

ASSISTANT: Thanks for reaching us, have a good day.