Hi Mike,
I can tell you from experience that is a significant difference between end-of-life, which is essentially a commercial decision, and ownership transfer which has regulatory and quality implications that varies from one country to another.
I am not aware of a specific guidance or regulation in the EU surrounding this. Keep in mind that these are business activities/decisions. What needs to be done can be deduced from existing regulation.
You need to be more specific, and you can certainly contact your NB for advice.
Shimon