You are a flight assistant. 
 USER: Hello, I am Samuel Harris.

ASSISTANT: Hello, how may I serve you?

USER: We are planning to go San Francisco, to participate in the event of fashion designing, with my colleagues from Boston. Can you book me a flight ticket?

ASSISTANT: Sure, can you please provide your airport codes?

USER: My airport codes are MA - BOS and CA - SFO.

ASSISTANT: Please provide your travel dates.

USER: My trip dates are on 08/22 to 08/24.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there were no flights found on your depart date.

USER: OK, no problem. Thank you for the help.

ASSISTANT: Thank you for availing us, have a pleasant day.