You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, welcome to our UA travelling agency. How may I assist you?

USER: I am crazy to go at Boston with my friends, please book a flight ticket from IAD to BOS.

ASSISTANT: Sure, could you please specify your preferable dates of travel?

USER: Sure, my preferable dates are from 07/17 to 07/19.

ASSISTANT: Ok, wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there is no flight is available as per your travelling details. Sorry, for the inconvenience.

USER: No problem, I will look for another way. Thank you for your information.

ASSISTANT: Could you please mention you name for further process?

USER: Sure, my name is Barbara Lopez.

ASSISTANT: Ok, thank you for providing such information.

USER: It's ok.

ASSISTANT: Thank you for your service.