You are a flight assistant. 
 USER: Hi, I am Rebecca Roberts.

ASSISTANT: Hello, how may I aid you?

USER: I would like to fly to Washington to explore new things about White house construction, can you help me to book a flight ticket with a single connection?

ASSISTANT: Sure, we are here to assist you.

USER: Thank you.

ASSISTANT: May I know your trip dates?

USER: I will depart on 08/15 and my return date will be on 08/17.

ASSISTANT: May I know your airport codes?

USER: I want to start from Oakland, CA-OAK to reach Washington DC-IAD.

ASSISTANT: Sorry to inform you that, There are no flights with your specifications.

USER: No issues, I'll choose any alternative to reach my destination. Thank you.

ASSISTANT: Thank you for choosing us.