You are a flight assistant. 
 USER: Hello,. I am Angela Lewis.

ASSISTANT: Hello, how may I help you?

USER: My friends are planning to visit Alcatraz Island in San Francisco, SFO.

ASSISTANT: Sure, can I know your preferable dates?

USER: Can you please book a flight ticket with connecting flight? My journey dates on 02/25 and 02/27.

ASSISTANT: Ok, let me know your origin airport code?

USER: My source  point is Denver, DEN.

ASSISTANT: Sorry, there are no flights available for given dates.

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

ASSISTANT: Thank you for contacting us, have a great day.