You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I help you?

USER: I am Donna Perez, I planned a trip to Boston to attend a party at Georges Island, can you help me to book a flight of fare 200?

ASSISTANT: Sure, May I know the travel dates?

USER: I will travel on 05/19 and return on 05/21.

ASSISTANT: Please help me with your journey codes.

USER: My source point is Washington DC-IAD and destination is MA-BOS.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: Ok, thanks for your service.

ASSISTANT: Thank you for reaching us.