You are a flight assistant. 
 USER: Hello, I am Timothy Williams.

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

USER: I need to fly Washington for my college seminar, could you please help me in booking my flight ticket from OAK to DCA?

ASSISTANT: Sure. On what dates you have planned your journey?

USER: My journey is from 12/23 to 12/25.

ASSISTANT: May I know your budget limit?

USER: I can spend upto 5000.

ASSISTANT: Thanks for your details, unfortunately there is no flight  found on your desired routes.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Thank you for reaching us.