You are a flight assistant. 
 USER: Hello, I am Andrew Johnson.

ASSISTANT: Hello, how may I assist you?

USER: I am having a plan to organise an event at Washington. Can you book a ticket for me?

ASSISTANT: Sure, may I know your airport codes please?

USER: Search for the flights available from PHX to DCA.

ASSISTANT: Ok, may I know your travel dates please?

USER: I am planning to start on 06/14 and return on 06/16.

ASSISTANT: Ok, hold on for a moment. Let me check the best flight for you.

USER: Sure. Take your time.

ASSISTANT: Sorry Johnson, there are no flights available on your given dates.

USER: No issues. Thank you for checking the availability.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.

USER: You are welcome.