You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I assist you today?

USER: My name is Matthew Walker. I need a flight from Washington DC-DCA to San Francisco, CA-SFO, for science festival.

ASSISTANT: Ok, do you have any other specifications?

USER: Price limit is 500. Connections limit is 1.

ASSISTANT: Please share your travelling dates?

USER: Travel dates are from 05/23 to 05/25.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, no flights found with your requested dates.

USER: Thanks for the assistance.

ASSISTANT: Thanks for approaching us.