Swap top to bottom layer copper without flipping

I created a complete layout but unfortunately used the wrong layer for all copper traces. Now I’d like to swap top layer chopper traces into bottom and vice versa, WITHOUT flipping their layout.
I couldn’t find a way so far.
Any idea?
Best regards

Besides exporting the file, then modifying it manually or with a tool, and reimporting, I don’t know of a method to do so.

Best to just redo it on the bottom side. It will be painful, but overall quick.