You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Gary Anderson.

ASSISTANT: How may I aid you?

USER: I am planning to visit Detroit, can you please book me a ticket in direct flight?

ASSISTANT: Sure, could you please share your journey dates?

USER: My preferable journey dates are from 09/19 to 09/21.

ASSISTANT: May I know your airport codes?

USER: My nearest airport codes of travelling are from SFO to DTW.

ASSISTANT: I have found a direct flight from Frontier airlines, shall I proceed?

USER: Please reserve my ticket with this flight.

ASSISTANT: Ok, your ticket has been booked.

USER: Thank you for booking my ticket.

ASSISTANT: Welcome.