You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you today?

USER: I am Michael Collins, can you help me by booking a flight with 500 price limit?

ASSISTANT: Sure, I am glad to help you in booking, please share your travelling dates?

USER: My travelling dates are 05/18 and 05/20.

ASSISTANT: May I know your journey airport codes?

USER: My airport codes are DCA and PHL.

ASSISTANT: Sorry, no flights as per your details.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us.