You can change the child variant products to singles and singles to child products by simply exporting the parentage column. This is useful if you have received any error from Amazon or eBay that indicates you can’t create a product with this variation type because they have removed the variation types from that particular category. You can also do the opposite version of this action by merging single products as child products under the parent.
Here are the steps you need to follow:
1- Go to the “Inventory”, select related parent and child products and click to “Export>Custom…”
2- Select the fields “Parentage, Parent SKU, Variation Options and Variation Types” from the custom fields export selector and click the export.
3- Download the file from the “Notifications” form at the top right of the screen.
4- Open the exported file, delete the data inside the parent_sku, variation_options, variation_types that belongs to child products and change the value “Child” to “Single” in the parentage column.
5- Upload the file back into the SA from the top right.
After this action your child products will be single products.