You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: Myself Jennifer White. Please book a flight ticket from IAD to OAK, will you please help?

ASSISTANT: Sure, I'll help you. Can you tell me your trip dates?

USER: My travelling dates are on 12/11 and 12/13.

ASSISTANT: Ok. Wait a minute. Sorry Jennifer, there is no flight available.

USER: It's ok. Thank you for the information.

ASSISTANT: Most welcome.