You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Jeffrey Baker. Can you book ticket from DFW to IAD. I Want to attend the business meeting in Dallas.

ASSISTANT: Could you please provide your travelling dates?

USER: Well, my preferable dates of travelling are from 03/27 till 03/29.

ASSISTANT: Sorry, there is no flight available at your request.

USER: It's ok.

ASSISTANT: Thank you for contacting us. Have a nice day.

USER: Thank you for your good service.