I am trying to update an assembly in a Composer document that I have added parts to.  It is a subassembly of a larger machine.  There are 2 machines in the document so I do not want to update the document as it will erase the other machine.  I would like to only update the one machine.  When I try to update the desired assemblies, I get the error message, "The operation cannot be performed because of cloned actors."  What do I need to fix in order to update the parts I need?