You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. May I know your good name, Please?

USER: Gregory Moore is my name.

ASSISTANT: How can I help you for the day?

USER: Please book a ticket to San Francisco, CA-SFO from Washington, DC-IAD for sports event.

ASSISTANT: OK. May I know your travel dates, Please?

USER: Travel dates are 01/26 to 01/28.

ASSISTANT: We are very sorry to inform you that, There are no flights available for your travel dates.

USER: Thanks for the help.