How to re-import into Twinmotion 25.2 a corrected updated SketchUp 19 model?

I have a huge model 60 floors tall 600 x 400m land already in Twinmotion 25.2

But as I progress in the renderings I see mistakes that hadn’t noticed in SKU.

I can’t seem to find a way to re import it from SketchUp 19 into Twinmotion 25.2 and merge the existing with the newly corrected file (new name just by number).

I have my model in Twinmotion with all the lights, waters, palm trees (seaside building).

I am tired to restart doing all the light emitters and materials.

Can’t find a YouTube that explains it clearly like I am five (okay fifty five)

Ultimately I want to take it into Unreal Engine 5.2.

What’s the trick? Thank you to any of you out there