Can I go personally to process a passport? It's just that I can't get an appointment. The phone they gave is disconnected. Thank you in advance for your help.

It is not safe to go without an appointment. But if there is space available they pass. Same at Riverside.

If you can go without an appointment ,,, you just have to wait a little longer than those who have an appointment, but if they take care of you

That is what I want to know if they can help you with an appointment at the one in San Bernardino or the one in Riverside or the one in Los Angeles, which is better if they attend without an appointment?

I can process my passport personally and not make an appointment or not

Only with appointments is any procedure.