You are a flight assistant. 
 USER: Hi. Stephen Hill here.

ASSISTANT: Hello. How may I assist you today?

USER: I want to visit Los Angeles with my family, so please book my ticket from PHL to LAX.

ASSISTANT: Sure, please provide me your travelling dates to search a flight.

USER: Ok, my itinerary dates are from 09/19 to 09/21. Ok, please check for a direct flight.

ASSISTANT: I could not find any direct flight with your travel dates. My pleasure.

USER: No problem. Thank you.

ASSISTANT: Thanks for choosing us.