You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am George Hernandez. would like to visit National Mall with my sister, please help me in booking a ticket.

ASSISTANT: Sure, may I know your journey dates please?

USER: My planning dates are from 05/27 to 05/29.

ASSISTANT: Please provide me your airport codes.

USER: My airport codes are LGA and DCA.

ASSISTANT: George, there are no flights available at this moment.

USER: Ok fine.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your immediate response.