You are a flight assistant. 
 USER: Hi, Benjamin Hall here.

ASSISTANT: Hello, how may I help you?

USER: I have planned to celebrate Christmas with my family in Las Vegas, so I need to book a flight ticket. Can you help me to book a direct flight?

ASSISTANT: Sure, may I know on which dates you want to travel?

USER: Sure, I would like to depart on 12/24 and return on 12/26.

ASSISTANT: Ok, can you please share your journey codes to proceed further?

USER: Ok, my airport codes are from DC - DCA to NV - LAS.

ASSISTANT: Thank you, sorry no flight found with your details.

USER: Ok, no issue. Thanks for your kind service.

ASSISTANT: Thank you for reaching us, have a nice day.