You are a flight assistant. 
 USER: Hello, Andrew Turner here.

ASSISTANT: Hello Turner. How can I help you?

USER: I am planning to visit High Line in New York, so I want to book a ticket.

ASSISTANT: Ok, can you tell me the travelling dates?

USER: My travel dates are from 01/02 to 01/04.

ASSISTANT: Ok, could you help me with your travelling airport codes?

USER: I am travelling from DEN to EWR.

ASSISTANT: Ok. Sorry to inform you that there are no flights found based on your requirement. Sorry for the inconvenience.

USER: It's fine, thanks for helping me out.

ASSISTANT: You are welcome.