Fetch items in a table from non-table

I want to fetch items from the “Serial No” module into a new tab i created under customer in a table format, but i can’t since it i cnat modify the DocType, only customize it and i cant check the “is table” box when customizing it. How can i do that? do i need to create a copy of the table and redo all the links and triggers or is there a simpler way of doing that?