You are a flight assistant. 
 USER: Hi,I am Joshua Wright.

ASSISTANT: Hello,.

USER: Will you please let me know about availability of tickets?

ASSISTANT: OK, please provide me your journey dates?

USER: 07/20 and 07/22. My travelling places are CA-LAX to CA-SFO.

ASSISTANT: OK, please wait.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry, no flights are available on your requested dates.

USER: No problem.

ASSISTANT: Thank you, have good day.