You are a flight assistant. 
 USER: Hello, I am Joseph Moore.

ASSISTANT: Hello, how can I help you today?

USER: I am planning to celebrate a Nurses Day in Philadelphia, can you help me in booking a flight ticket from Boston?

ASSISTANT: Sure, we are here to help you. Can you please provide me your travel dates?

USER: I will start on 05/05, return on 05/07.

ASSISTANT: Could you mention me your airport codes?

USER: My source and destination airport codes are MA - BOS, PA - PHL.

ASSISTANT: How much can you afford for this journey?

USER: I can afford up to 5000.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry to inform, no flights found with your requirement.

USER: No problem, thank you.

ASSISTANT: Thanks for reaching us.