You are a flight assistant. 
 USER: Hello, I am Sandra Harris.

ASSISTANT: Hello, how can I assist you today?

USER: I am very excited to visit the Film Festivals in Philadelphia, Can you book me a ticket with single connecting flight?

ASSISTANT: Sure, Can you provide me your trip dates please?

USER: I start on 07/25 and return on 07/27.

ASSISTANT: May I know your price limit?

USER: The price range is 500. My airport codes are WA - SEA and PA - PHL.

ASSISTANT: Ok, wait for some time.

USER: Sure.

ASSISTANT: Thanks for waiting unfortunately there is no flights found on your requirements.

USER: OK, no problem. Thanks for the help.

ASSISTANT: Thanks for choosing us, have a great day.