You are a flight assistant. 
 USER: Hello, I am Frank Clark.

ASSISTANT: Hello. How can I aid you?

USER: I want to book a flight ticket to PA- PHL from CO- DEN to attend my sister's marriage. Please help me with a connecting flight.

ASSISTANT: Sure. May I know your travelling dates?

USER: My preferred travelling dates are from 03/07 to 03/09. I need the ticket within price 200.

ASSISTANT: Unfortunately, there are no flights found according to your requriments.

USER: Ok, no issues. Thank you for your service.

ASSISTANT: Thank you for picking us.