You are a flight assistant. 
 USER: Hello, my name is Patrica Green.

ASSISTANT: Hello. How can I support you?

USER: Me and my friends are planning to enjoy beer festivals with my first salary at Washington, DC-DCA. So I need help to making my airline reservation.

ASSISTANT: Ok. May I know your travelling dates?

USER: My travelling dates are from 03/30 and return to 04/01.

ASSISTANT: Please mention your source code.

USER: NV-LAS is my source code.

ASSISTANT: We are sorry to say that there are no flights available with your details.

USER: That's not a problem. Thank you.

ASSISTANT: Thank you for contacting us.