You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I'm Christopher Allen. I am planning to attend music concert at Boston, can you please help me with booking a flight ticket?

ASSISTANT: When would you like to travel please?

USER: Sure, I would like to take off on 07/30 and return back on 08/01.

ASSISTANT: Can you please tell your travelling locations?

USER: My source airport code is IAD and the destination airport code is BOS.

ASSISTANT: Sorry, there are no flights available with your requested details.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you and have a nice day.

USER: You are welcome.