discard white over print in output

Here is an example action that removes the overprint setting for any fill that contains white. Strokes would be handled in a similar fashion. This would not account for blend modes such as multiply.

The action basically adds a new temporary object marked with a note, sets it to white, then selects all objects with the same white colour and then removes the overprint setting – then it will select only the temporary object marked with the note and deletes it.

I have not put it through exhaustive testing, however preliminary tests appear to work as expected.

NOTE: Global process CMYK white swatches with a name other than “White” will not be selected in this action! The Edit > Edit Colors > Overprint Black command does not have this limitation, however it can’t be recorded into an action.

White Overprint | Illustrator CC

When printing, the knock out was not previewed in the print window preview… but the actual output was indeed knockout and not overprint.

Switching between GPU preview and Overprint Preview can help to identify this visually.

This also works with a Save As - PDF, which was not clear from the link to the Adobe page.

If your file is a PDF file, then Acrobat Pro has a Print Production Preflight Fixup for this:

it's always best to completely delete white overprint instead of relying on automatisms.

Since you didn't post any details on the exact nature of your objects: you will need to use the appearance panel and the attributes panel.