You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Betty Evans here.

ASSISTANT: How may I aid you today?

USER: Can you please help in booking my flight to reach SFO from my home town PHL?

ASSISTANT: Sure, we are here to help you in booking. On which dates would you like me to book a flight ticket for you?

USER: Thank you. Sure, my trip dates are June 19th and June 21st.

ASSISTANT: May I know your depart and arrival timings?

USER: I need to return in the evening.

ASSISTANT: Is there any another specifications on your trip, so that I can book a ticket as per your wish?

USER: I want a single stop over in my journey.

ASSISTANT: Ok, please wait a moment.

USER: Ok, sure. Take your own time.

ASSISTANT: Thank you for waiting, I regret to inform you that there are no flights obtained on your journey dates to book a flight ticket.

USER: Ok, no problem. Anyways, thank you for the information.

ASSISTANT: Thank you for approaching us.