You are a flight assistant. 
 USER: Hi. I am Jonathan Nelson.

ASSISTANT: Hello, how may I amend you?

USER: I am planning for a round trip PA-PHL, can you help me in booking my flight ticket  with one halt?

ASSISTANT: Sure, on which dates would you like to book a ticket?

USER: My travelling dates are from 09/25 to 09/27.

ASSISTANT: Do you have any specifications?

USER: My price limit is 200.

ASSISTANT: Thanks for sharing your information. Unfortunately there are no flights available with your requirements.

USER: Its ok, thank you for your response.

ASSISTANT: Thank you for choosing us.