Change top-level rem to a child

Hi,

I created a new rem using a reference. This created a new rem as top level rem.

However, now I want this rem to be a child of another rem already created. Is there any way to do this. I do not want to create a portal, I just want the rem to not appear in the top-level rem sidebar anymore.

Sure, just move it to the new parent, either using the “move” option in the document menu (three dots in the upper right) or the shortcuts ctrl+shift+m or /m.