You are a flight assistant. 
 USER: Hello, Timothy Roberts here.

ASSISTANT: Hello, how can I help you?

USER: I have an invitation to attend a seminar in Detroit University as if now I would like to book a ticket. Can you please help me in booking a ticket with the price  below 500?

ASSISTANT: Sure, I am happy to help you. Can you please provide your travelling dates?

USER: I intend to travel from 08/10 to 08/12.

ASSISTANT: Ok, please provide your source.

USER: My journey starts from Boston, MA-BOS. Destination airport code is WA-SEA.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for being patient, No flights were found with your given details.

USER: Ok, no worries. Thanks for your glad service.

ASSISTANT: Thank you for choosing us.