generally, i can move namespace like this

namespace -force -mv “OLD_namespace” “NEW_namespace” ;

but it can be accepted with referenced node…

i create a scene fileA.mb (contained pSphere1 and referenced pCube1)
and i import fileA.mb with namespace…
so, fileA:pSphere1 and fileA:pCube1 is existing

namespace -force -mv “fileA” “:” ;
can’t clean the namespace “fileA”..

how can i make it?

If I understand you correctly, you want references to be in the the root namespace. Is that correct? I would caution very strongly against doing that. Which problem are you trying to solve by attempting to do this? Is there a reason for wanting to do it?