What should be done when encountering a document that has redactions or highlights that cannot be overwritten?

In the case of encountering a document with redactions or highlights that cannot be overwritten, the most appropriate course of action is to delete the markups. This response is correct because it directly addresses the issue of unwanted annotations or highlights that hinder the intended use or readability of the document. By removing these markups, you restore the document to a state where it can be accurately reviewed or processed without any distractions or obstructions caused by the existing redactions or highlights.

Moreover, updating the document format may not resolve the underlying issue of the non-removable markups and could lead to further complications. Re-uploading the document would be unnecessary if the issue is solely with the visible markups rather than the version or format of the document itself. Adding new redactions could complicate the document further instead of providing clarity or resolving the existing markup problems.

Therefore, deleting the markups ensures that you are addressing the redactions or highlights directly, allowing for a clearer and more usable document moving forward.