https://de.mathworks.com/help/simulink/slref/simulink.subsystemreference.convertallsubsystemreferenceblockstosubsystem.html
Simulink.SubsystemReference.convertAllSubsystemReferenceBlocksToSubsystem - Convert all Subsystem...
This MATLAB function converts all Subsystem Reference blocks in the model mdl to Subsystem blocks.
simulinkconvertsubsystem