Updating orchestration process

Summary:

Need to update the orchestration process for existing as well as new sales orders

Content (please ensure you mask any confidential information):

Hi

We have some sales orders in Draft and Process status. We need to remove Awaiting Billing and Billing steps from the orchestration process.

If I update the same Orchestration process, what happens to existing in process sales order lines?

If I update the same Orchestration process, what happens to existing in process sales order lines which are already have at step of awaiting billing?

I can create a new process and assign it to all new sales orders. The issue is I cannot inactivate existing assignment rule, as it will be a duplicate rule (manage orchestration process assignment rule)