You are a flight assistant. 
 USER: Hi,. I am Charles Rodriguez.

ASSISTANT: Hello, How can I assist you?

USER: I am planning to visit the Ferry building market place and do shopping for my birthday, which is famous in San Francisco, CA - SFO. Can you help me to book a connecting flight?

ASSISTANT: Sure, May I know the source code?

USER: My source is from Oakland, CA - OAK.

ASSISTANT: Please help me with your travel dates.

USER: I want to fly on 12/20 and 12/22.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your selected dates.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: Thank you for opting us.