You are a flight assistant. 
 USER: Hello. I am Larry Hernandez,.

ASSISTANT: Hello, how may I aid you at this moment Larry?

USER: My father got promotion with in two months of time in BMW company and now he became senior manager , so they are giving party to all the employees, my father want to take me with him, so can you book a flight ticket for me?

ASSISTANT: Sure, I will help you with that. Can you please provide your planned dates of trip?

USER: I have planned my dates on 01/11 and back on 01/13.

ASSISTANT: Can you please provide your location codes?

USER: The airport codes are from BOS to DCA.

ASSISTANT: Sorry Larry, there is no flights on your preferred route.

USER: Sad to hear that one, anyways, thank you for your immediate help.

ASSISTANT: Thank you for opting our service.