In California every alcohol server and manager at an on-sale venue holds a Responsible Beverage Service certificate. A new hire has 60 days from the first day of work to register, train and pass; the exam is passed within 30 days of the training; the certificate lasts three years and can be renewed in its last 90 days. It belongs to the person, so it comes with them from another job.
A person goes on a bar shift only if, on that date, they hold a certificate in force or are still inside their first 60 days.