You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Thomas Brown.

ASSISTANT: How can I help you?

USER: Can you please help me for booking a flight ticket from CA-SFO to TX-DFW, can you help me?

ASSISTANT: Sure, will you provide your travelling dates?

USER: My departure day is 02/28 and return day is 03/01.

ASSISTANT: Please give me a moment.

USER: OK.

ASSISTANT: Sorry to say that Brown, there is no flights found under your requirements.

USER: Thank you.

ASSISTANT: Thanks for reaching us.Have a nice day.