You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you?

USER: I would like to go for round trip with my friends. Can you please book a direct flight for me? Price limit should not exceed 1000.

ASSISTANT: Sure can you please provide your travel dates?

USER: My travelling dates on 07/16 and 07/18.

ASSISTANT: May I know your good name please?

USER: My name is Margaret Miller.

ASSISTANT: Can you please share your round trip code?

USER: My airport code is Philadelphia, PHL.

ASSISTANT: Please wait for a while, I will check and get back to you.

USER: Sure.

ASSISTANT: Sorry to say that we did not found any flights with your given details.

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks for choosing us.