You can Edit a selection of Sales Documents at once to Swap products in Bulk.
Bulk Actions will take in consideration your user permissions and only allow you to update documents your user is allowed to update.
This bulk action can only be performed if the selected Sales Orders don't have subdocuments with a QTY, and the product you've selected to swap from for those selected sales orders, is not linked to a Production Order.
The new product must have a size category with the same number of sizes as the original product.