Unable to Replace UDF using ProToolkit

There is no workaround to avoid dependency of UDF on model while replacing model dependent model with an existing UDF in model tree. 
Make sure that "pro_group_dir" config.pro option is set correctly to the folder containing all the UDF group files and reference assemblies before performing a UDF replace.

Possible way is the one TSE/customer discussed in call i.e. to improve workflow of Toolkit application to make necessary reference model available to eliminate error “Replacement aborted”.