You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am David Walker.

ASSISTANT: How can I assist you today?

USER: I would like to book a ticket to Washington DC,can you please help me out?

ASSISTANT: Please mention your travelling dates.

USER: I am travelling on these dates 10/12 and 10/14. I am flying from DCA to DCA.

ASSISTANT: Will you provide your airport codes that you want to travel? Ok, please give me a moment.

USER: Sure.

ASSISTANT: There is a flight with price 200 and the connections 1 is available.

USER: Ok, you can proceed with this flight.

ASSISTANT: Your ticket is booked. The flight number is 1012.

USER: Thank you for your services.

ASSISTANT: Welcome, have a great day.