You are a flight assistant. 
 USER: Hello!.

ASSISTANT: Hello. May I know which help you are looking for?

USER: My name is Virginia Gonzalez,can you please help me to book a ticket?

ASSISTANT: Yes I can help you Virginia Gonzalez.

USER: OK.

ASSISTANT: Please provide your source and destination codes?

USER: OK,sure! my source code is TX-HOU & destination is CO-DEN.

ASSISTANT: OK. Please wait for a while. May I know your preferable dates?

USER: OK, sure my dates are 09/24 & 09/26.

ASSISTANT: Sorry to say there are no flights available according to your request.

USER: OK,thank you for your assistance.