Context

Customer is developing products in a formal and defined process. Using Change Action allows them to control who can work on a change and setting primary & secondary revisions allow them to work with traceable development steps/design iterartions.
 

When customer is executing the Change Action with a revision A.1, he sets the object to Frozen, sends STEPS to external customers for their approval (e.g. ERP System, Workshop, External Customer, etc) and sets the CA to In Approval. This creates the approval task, which is then rejected with comments being made. CA is back to In Work and assignee creates a new revision on the Frozen object, creating a revision A.2 In Work. after making the design iteration, the A.2 is set to frozen, sends STEPs to external customers  for their approval and CA set to In Approval. Customer wants to leave revision A.1 in Frozen and revision A.2 to be Released (for production or other).
 

Question

With many parts or subs in the CA there is a need for clarity in the results

• If both A.1 and A.2 are released through the CA how what's the easiest way to communicate to not use?
• How can we force the CA Realized Changes to only release the latest secondary revision?
• How do we minimize the potential for errors (A.1 & A.2 Released)?
• How to go about design iterations in a controlled formal process?

Looking forward to your experiences and/or ideas on this topic!