You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you?

USER: I want to book a ticket from LAS to OAK, can you help me?

ASSISTANT: Sure, I am here to help you. Please let me know your travel dates.

USER: My travel dates are 12/26 and 12/28.

ASSISTANT: May I know your name?

USER: Myself Matthew Williams.

ASSISTANT: Williams, please be on hold for sometime.

USER: Ok.

ASSISTANT: Sorry Williams, there are no flights available on your preferred dates.

USER: No problem, thanks for checking.

ASSISTANT: You are welcome and thank you for contacting us.