Check this gist: update_map_in_loop.md · GitHub
It’s a Livebook, so you can copy and paste it into your Livebook server and play with it.
If you need more explanation, I can provide it. I am pretty sure there are more elegant ways to achieve this, but this should be good enough as a start.
The problem with your solution is that it’s not “reducing” the order (keeping the changes for all iterations), just returning the list of modified orders. Each order (item of the returned list) is the order modified but just for a single product.
Hope this helps a bit.
