You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I am Stephen Campbell. Please help me in booking flight ticket from SFO to DFW?

ASSISTANT: Sure Stephen Campbell, I will help you with that. Can I have your travel dates please?

USER: My travelling dates are 07/25 and 07/27.

ASSISTANT: Ok, please wait a moment to check flight availability.

USER: Ok, sure.

ASSISTANT: Sorry Stephen Campbell, no flight is available to you on your dates.

USER: Ok, fine thank you for checking.

ASSISTANT: Thank you for choosing us, have a good day.