How do I share an animation asset on different skeletons, instead of creating a new retargeted asset?

In Unity, for Humanoids, the clip asset can be shared.
In UE it seems I have to perform retargeting and result in a different retargeted clip, which means each skeleton shall have its own set of clips. Is it possible to reuse the same clip on different skeletons, and the clip is retargeted on the fly?

I totally forgot that I had asked about this a long time ago. I got some answers but there’re still things left unanswered, and perhaps there are things that have changed.

So, can I share an animation asset on a different skeleton, and how different can that skeleton be? Names, hierarchy, scaling, etc?