You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what can I do for you?

USER: I am Eric Lopez. I am planning for a round trip with my colleagues to Washington DC-IAD, can you please book a flight ticket?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travelling dates are 07/01 and 07/03.

ASSISTANT: How much can afford for ticket?

USER: I can spend upto 500 for flight ticket.

ASSISTANT: Wait a minute.

USER: Sure.

ASSISTANT: We found a flight on spirit airline, flight number as 1015 with the fare of 100. Shall I proceed?

USER: You can proceed.

ASSISTANT: Your ticket has been booked.

USER: Thank you.

ASSISTANT: Thank you for opting us.