Please expand article on replacing design file header. This should also include additional detail on how to deal with references and additional models within the file that the design file header is to be replaced.
I assume this post is relating to this old Wiki article.
https://communities.bentley.com/products/microstation/w/microstation__wiki/17178/how-to-replace-design-file-header
Can you expand on what your queries are relating to and possibly supply further details including example files, screen captures etc.
RegardsAndrew BellTechnical SupportBentley Systems