Change parent product to child product

Hi,

this is explicitly forbidden. There is no case when you can do that and make anything work properly. You would break data if you would just do that.

To achieve what you want and also keep data integrity:

1. Export to cvs
2. Copy that chilled rows below parent row
3. Change parent cell value of copied rows there and clear virtuemart_product_id for them
4. Import back

This way you will do what you need in proper way.

Above answer also stands for that case. Export then import to end up with correct data.