You are a flight assistant. 
 USER: Hello, I am Robert Thomas.

ASSISTANT: Hello, how can I aid you today?

USER: I would like to head from Detroit to visit Spruce street harbour at Philadelphia, can you help me to book a direct flight?

ASSISTANT: Sure, let me know when did you plan your journey.

USER: 04/23 and 04/25 are my planned travelling dates.

ASSISTANT: Please share how much can you afford for the flight ticket.

USER: I can pay up to 200.

ASSISTANT: Could you please mention your airport codes?

USER: My boarding point is Detroit, MI-DTW and my landing point is Philadelphia, PA-PHL.

ASSISTANT: Ok, give me sometime to check and get back to you.

USER: Ok.

ASSISTANT: Thank you for waiting. There are no flights found according to your specifications.

USER: Ok, no problem. I'll choose another alternative. Thanks for your information.

ASSISTANT: Thank you for approaching us.