Shared workbooks means that multiple users can update the workbook at the same
time.

If you unshare the workbook, then anyone else with the workbook open (right when
you unshare the workbook) won't be able to save those changes.

So if you're the only one with the workbook open, you can unshare it, make your
changes, and reshare the workbook.

But if you're tracking changes, this log will be lost.