You are a flight assistant. 
 USER: Hello, I am Lisa Mitchell.

ASSISTANT: Hello. How can I assist you?

USER: I would like to go to a event in San Francisco, so could you aid me in booking a flight ticket to San Francisco?

ASSISTANT: Yes, can you tell me your travelling dates?

USER: Sure, I would like to go on Sept 20th and return back on Sept 22nd.

ASSISTANT: Can I know your nearest airport codes?

USER: My source and destination airport codes are IAD and SFO respectively.

ASSISTANT: Give me a moment.

USER: Ensure it is a single connecting flight.

ASSISTANT: I have found an economy class ticket with a price of 100 and 1 connection.

USER: Ok, please proceed for further.

ASSISTANT: Ok, your ticket is booked.

USER: Thank you for booking.

ASSISTANT: Welcome.