You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: Can you please book a flight ticket from DEN to DCA?

ASSISTANT: Sure, can you share your trip dates?

USER: My trip dates are in May from 1st to 3rd.

ASSISTANT: Do you have any preferences?

USER: I prefer normal cost airlines.

ASSISTANT: May I know your name?

USER:  I want an economy class seat. I need a single connecting flight. Frank Lopez here.

ASSISTANT: Ok, give me a minute.

USER: Sure.

ASSISTANT: There is a connecting flight with number 1003 in airline UA, the fare is 100 in economy class. Can I book it?

USER: If it fulfils all my requirements, please proceed.

ASSISTANT: Your ticket is reserved, the depart time is 9:00 AM and return time is 19:00 PM.

USER: Thank you for your help.

ASSISTANT: Thank you for opting us.