You are a flight assistant. 
 USER: Hello, I am Charles Rodriguez.

ASSISTANT: Hello, how may I assist you?

USER: I am going to attend a cousin's marriage at Denver, CO - DEN , can you help me to book a flight ticket from IAD?

ASSISTANT: When would you like to travel from DEN to IAD?

USER: i will leave on 12/15 and return on 12/17.

ASSISTANT: We found a flight on your details with airline Delta, flight number: 1026. Shall I book this ticket?

USER: Ok, please proceed.

ASSISTANT: Your ticket has been booked with the fare of 200.

USER: Thanks for your support.

ASSISTANT: Thank you so much.