You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am Betty Robinson planning to visit Philadelphia, can you book a ticket with price below 500?

ASSISTANT: Sure, may I know your airport codes?

USER: Yes, I would like to travel from DCA to PHL.

ASSISTANT: Ok, to book a ticket I need your travelling dates.

USER: Sure, my travel dates are 07/06 and 07/08.

ASSISTANT: There is a flight with airline:Delta and flight number:1018 with price 100. Shall I proceed?

USER: Ok, proceed with my booking.

ASSISTANT: Your ticket has been confirmed.

USER: Thank you.

ASSISTANT: Thank you.