This is how the seller can do it, atleast on Amazon India.

Swapping the details completely triggers AI based flags and often causes the change to be manually reviewed.

But the seller can add a variant of the product (like size or color). But the seller instead adds a completely different product he intends to swap the original product with. Now the listing will show two completely different products as variants on a single product listing. Then the seller removes the old variant. Nothing gets flagged. No manual review.

This has been around for long and a very popular trick with shady sellers on Amazon in India. I don't think Amazon never figured it out. For whatever reason, Amazon turns a blind eye to this practice.