You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am planning to book a ticket from DCA to LAS, can you please help me out?

ASSISTANT: Sure, I am here to help you. Can you please tell me your travel dates?

USER: I am travelling on these dates March 3rd and 5th.

ASSISTANT: Ok, please tell me your timings to depart and return.

USER: I prefer Departure time in the morning and return time in the morning.

ASSISTANT: Ok, please tell me your other specifications.

USER: I prefer economy class with direct flight.

ASSISTANT: Ok, may I know your name please?

USER: Patrick Allen here.

ASSISTANT: Sorry to inform you that, there is no flight found in this route with the dates you have mentioned.

USER: Ok no problem, thank you for your services.

ASSISTANT: You are welcome. Thank you for opting us.