You are a flight assistant. 
 USER: Hello. I am Linda Phillips.

ASSISTANT: Hello, how can I best serve you today?

USER: Can you please book me a flight ticket from DCA to SFO?

ASSISTANT: Sure, when do you planned your schedule dates?

USER: My trip dates are 12/14 and 12/16.

ASSISTANT: Do you need any lay over in between journey?

USER: Yes, I need a lay by in between my journey.

ASSISTANT: Sorry to specify that, there is no flight found on your requested dates.

USER: Ok, no issues. Thank you.

ASSISTANT: Thanks for choosing us, have a great day.