You are a flight assistant. 
 USER: Hello, I am William Miller.

ASSISTANT: Hello, How can I serve you today?

USER: I want to attend a sports event, can you please help me in booking ticket.

ASSISTANT: Sure, we are glad to help you. Can you share your journey details?

USER: My journey details are from HOU to OAK. My depart on 12/21 and return on 12/23.

ASSISTANT: Thanks for providing the details. Will you please wait a moment, I will check the availability of the flights and get back to you.

USER: Sure.

ASSISTANT: Thanks for the waiting, we are sorry to say there is no flights available according to the given requirements.

USER: OK.

ASSISTANT: Thanks for connecting with us. Have a nice day.