You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you?

USER: I am Thomas Hall. Can you please reserve me a flight ticket which is having it's depart time in the evening?

ASSISTANT: Sure, may I know your airport codes?

USER: I would like to travel from IAD to LAS.

ASSISTANT: Is there any class preference?

USER: No.

ASSISTANT: May I know your scheduled travel dates?

USER: I have planned to travel on Feb 15th and return on Feb 17th.

ASSISTANT: Do you have any other specifications?

USER: I prefer connecting flight.

ASSISTANT: We found a connecting flight in Spirit Airlines with flight number 1020 having an economy class departs in the evening at 1:00 AM. Shall I proceed?

USER: Ok, please book this ticket.

ASSISTANT: Your booking has been confirmed.

USER: Thank you.

ASSISTANT: Thank you for opting us.