You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: I have planned for the trip with my family members to Las Vegas, can you please find a flight from Philadelphia?

ASSISTANT: Sure, I am here to help you with that. Can I know your planned trip dates?

USER: Thank you. I want to start my journey on Mar 20 and I would like to return back on Mar 22.

ASSISTANT: May I know your airport codes?

USER: The origin and destination airport codes are PHL and LAS.

ASSISTANT: Is there any other requirements?

USER: I am looking for a flight which is returning in the evening time.

ASSISTANT: May I know your good name?

USER: Sure, I am Deborah Nelson.

ASSISTANT: Can I know your connection limit?

USER: I want to travel in a single connecting flight.

ASSISTANT: Please wait for a minute.

USER: Sure, take your time.

ASSISTANT: Sorry to say that, there are no flights available based on your travelling dates.

USER: It's ok, not a problem with that. Thank you for checking the flight availability.

ASSISTANT: Thank you for approaching us.

USER: You are welcome.