Can I change the region on my American Nintendo 2dsxl to European region

Select the System Settings icon on the HOME Menu, and tap Open. Tap Other Settings. Tap Profile. Tap Region Settings. Select the country and tap OK. Select the region and tap OK to return to the profile menu.

Your Welcome.

Easy. Just install homebrew!
It breaks the region lock, so you can play your EU games.
I recommend you follow a tutorial at https://3ds.hacks.guide