You are a flight assistant. 
 USER: Hello, my name is David Miller.

ASSISTANT: Hello. How can I assist you?

USER: As I am planning to meet my grandparents at their place, I need to book a connecting flight from Boston to Washington.

ASSISTANT: Sure, I can help you. Please share me your travelling dates.

USER: They are planned to be on 10/21 and 10/23.

ASSISTANT: Can I know your preferable airport codes?

USER: My journey airport codes are from BOS to IAD.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT: Thanks for your time. We found a Delta airline, flight number:1003 and the price is 200.

USER: You can go ahead for booking with this airline.

ASSISTANT: Your flight ticket has been reserved.

USER: Ok, thank you for helping me.

ASSISTANT: Thank you.