I was served a Summons of Supreme Court today. A Collection Agency is sewing me on behalf of a 4 year old Dentist Bill. I called up Collection Dept. and set up a payment plan. Is there anything I need to do, Before a Court date is issued?

Yes. You need to appear in Court. It is my feeling that the collection agency will get a Judgment against you on behalf of the Dentist but will not attempt to collect on it as long as you keep your payments current. If you become delinquent, then they will enforce the Judgment.

This is standard practice.

My paymnent plan was arranged with the Collections Sueing me. What more do I need to do? For California Law

Did you read what I posted? That's what you need to do.

Unless the collection agency guaranteed IN WRITING that they will drop the lawsuit... well, I've already said it once.