You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: I am Justin Anderson, can you help me to book a flight from DTW on Jan 19?

ASSISTANT: Sure, I am here to help you out. May I know your return date please?

USER: I am planning to return on 21st Jan.

ASSISTANT: May I know your destination airport code please?

USER: It is OAK, so please book a flight to Oakland.

ASSISTANT: How much you can afford for airfare?

USER: 5000 is my trip budget.

ASSISTANT: UA airlines is available in your route with the ticket fare of 100 in economy class, shall I proceed with the booking?

USER: Proceed with booking.

ASSISTANT: Your ticket is booked with the flight-1003.

USER: Thank you.

ASSISTANT: Thank you for choosing us.