In Magento 2, You can update already existing products using REST API. You need to call the updated product request URL to perform the update action.
For Update Product, you need to call the PUT method as action Type.
Action: PUT
Request URL: <YOUR_SITE_URL>/rest/V1/products/<SKU>
Replace YOUR_SITE_URL with the actual site URL and SKU with your product SKU which you want to update data.

Thanks ! Two questions.
1) Can I change just the attribute_set_id of a product via de REST API? How can I do that?
2) You specify “magento2ee” in the URL. Can this be done in de Community edition?
Thanks ! Two questions.
1) Can I change just the attribute_set_id of a product via de REST API? How can I do that?
2) You specify “magento2ee” in the URL. Can this be done in de Community edition?