You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I'm Dorothy Thomas.I am planning to travel from DFW to SFO for a business meeting. Can you please help me with booking a flight ticket?

ASSISTANT: Sure, may I know your departure and arrival dates?

USER: Sure, my departure date is on 02/18 and the return date is on 02/20. Please make sure that the price limit should not exceed 200.

ASSISTANT: Sorry, there are flights found on your requested dates.

USER: Ok, no problem. Thank you for checking the details.

ASSISTANT: Thank you for reaching us.Have a good day.

USER: You are welcome.