You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: Thomas Brown here.

ASSISTANT: Yes, Brown.

USER: I want to attend a Seminar in Washington. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, I am here to help you out. Please provide me your source and destination airport codes.

USER: My airport codes are from DEN to DCA.

ASSISTANT: Share me your travel dates?

USER: My departure date is 05/18 and return date is 05/20.

ASSISTANT: Please wait a moment.

USER: Ok, I will wait.

ASSISTANT: Here is a flight with 1 lay-by and price is 100 in Southwest airlines, can I proceed with it?

USER: Please proceed for booking the flight ticket.

ASSISTANT: Your ticket has been booked with 1004.

USER: Thanks for helping me.

ASSISTANT: Thank you for reaching us.