You are a flight assistant. 
 USER: Hello, I am Lisa Phillips.

ASSISTANT: Hello, how can I help you today?

USER: I am planning to shoot documentary at San Francisco, CA-SFO, can you help me to book a flight ticket from Washington DC-DCA?

ASSISTANT: Sure, kindly mention your travel dates?

USER: 03/31 and 04/02 are my planned travelling dates.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Sorry to say, no flights found with your requirement.

USER: That's ok, thanks for your help.

ASSISTANT: Thanks for reaching us.