You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Ashley Thomas. I have to give a seminar at New York, so can you please reserve a flight ticket which will depart in the evening time?

ASSISTANT: Ok, on which dates you are planning to travel?

USER: I have planned my journey dates in the month of May and the dates would be 25 and 27.

ASSISTANT: Can you please tell me your airport codes?

USER: Sure, my regional airport codes are from DEN to EWR.

ASSISTANT: Ok, do you have any other requirements?

USER: I need a flight in economy class and must have one limit in my journey.

ASSISTANT: Sorry Ashley, there is no flights available with your requirement.

USER: No problem with that one, I can prefer any other source. Thank you for your quick help.

ASSISTANT: Most welcome.