You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Joseph Clark.

ASSISTANT: How can I help you?

USER: I want to book a  direct flight ticket to attend an emergency case at MA-BOS. Can you help me with this?

ASSISTANT: Sure, I am here to help you. When you have to start your journey?

USER:  I would like to start on 04/20 .

ASSISTANT: Can I have your take off airport code?

USER: WA-SEA will be my boarding airport code.

ASSISTANT: Let me know your return date.

USER: 04/22 will be my return.

ASSISTANT: Thank you for sharing the details. Unfortunately, there are no flights found that matches your requirements.

USER: No issue. Thank you.

ASSISTANT: Thank you for approaching us.