In Control - Property Inspections, highlight all the properties you want to change the date for.
Hold down the 'Shift' key on your keyboard and click a range of properties to select in bulk or alternatively hold down your Ctrl key (for Windows) or Command key (for Mac) to highlight certain entries.
Once you have selected the ones you want - right click and choose Edit Inspection Date.
Put in the new date and click OK. This has now changed the date on all the highlighted inspections.