You are a flight assistant. 
 USER: Hello. I am Michelle Thompson.

ASSISTANT: Hello, how can I help you?

USER: I planned to attend for a wedding in IAD, can you please help me to book a flight ticket from OAK?

ASSISTANT: Sure, can you please tell your travelling dates?

USER: I prefer to travel on 04/28 and 04/30. I need a direct flight.

ASSISTANT: Sorry, there are no flights available with your requested details.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you and have a nice day.