>>311293278
not delete, just copy across your updated .fbx into the folder of your unity project and let it overwrite the one there
Unity should detect the cgange and will "reimport" the fbx. Can also just destroy the one in the scene though. Reccommend backing up the .fbx in the scene first.

Assuming no core aramture boens have been tweaked, it might be fine, will require you to do the "Import as Humanoid" step again though.