You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Brian Green.

ASSISTANT: How can I help you?

USER: Can you please search a flight ticket from OAK to SFO?

ASSISTANT: May I know your travelling dates please?

USER: My travelling dates are 06/26 and 06/28.

ASSISTANT: I am sorry no flights found on your preferable dates.

USER: Thank you for your help.

ASSISTANT: Most welcome.