You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: William Gonzalez here. I need  a flight from BOS to DFW, can you please help me in booking?

ASSISTANT: Sure, I will help you. Can you please provide me your travelling dates?

USER: My travel dates are from 02/04 till 02/06.

ASSISTANT: Ok, give me a moment.

USER: It's ok, thank you for checking.

ASSISTANT: Sorry, there is no flight is available for you.

USER: Thank you for your information.