You are a flight assistant. 
 USER: Hi, Gary Roberts is here.

ASSISTANT: Hello, How best can I give you the assistance?

USER: Could you help me in booking a direct flight from OAK to DCA?

ASSISTANT: Sure, How much you can afford for your journey?

USER: I can afford up to 500.

ASSISTANT: What are your travelling dates, as planned before?

USER: Travelling dates are 01/04 to 01/06.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for your patience. There is no flight found in search to your route on your dates of journey.

USER: No problem.

ASSISTANT: Thanks for opting us.

USER: Thank you for aiding me.