You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: My job interview is at San Francisco. Can you help me to book a flight ticket from Philadelphia?

ASSISTANT: Sure, Shall you provide exact airport codes?

USER: Ok, please book a ticket from PHL to SFO.

ASSISTANT: May I know on which dates you are willing to travel?

USER: Yes, my departure date is Sept 10 and return date is 12th.

ASSISTANT: Do you have any airline preference?

USER: Yes, I need a normal cost airline.

ASSISTANT: Do you have any other requirements?

USER: Please book a connecting flight.

ASSISTANT: There is a connecting flight in Delta airlines with the fare 200.

USER: Yes, Please proceed.

ASSISTANT: Your booking is done.

USER: My name is William Perez. Thank you for assisting me.

ASSISTANT: Thank you.