You are a flight assistant. 
 USER: Hi, I am David Martinez.

ASSISTANT: Hello, how may I support you?

USER: I have to do shopping at San Francisco, CA - SFO for my sister's marriage. Can you please book me a flight ticket?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travelling dates are 11/22 and return on 11/24.

ASSISTANT: Please provide your source code.

USER: My origin airport code is Washington, DC- IAD.

ASSISTANT: We found a flight with number 1003 and AA as airline. The cost of the ticket is 200.

USER: Please proceed for booking.

ASSISTANT: Your ticket is booked.

USER: Thanks for booking my ticket.

ASSISTANT: Thank you for opting us.