Hi Joanne,
Apologies for the huge delay in responding to your request.
If I understand your scenario correct, the capability to replace variables/actions now exists.
If you configure an action's output and use these parameters in subsequent actions, you can replace that output with a newly created variable/object - If this results in variable references being orphaned, you will be given a "Delete or Replace" experience in the Variable panel to fix any broken references.
You can also delete the action, which will result in the same behaviour.
Hopefully this solved the problem you were encountering. If not, please do reach out again to work through the problem further.
Regards,
Kate