Bulk Edit the Due Date for Multiple Task Items

This example moves the due date of all selected task items by four weeks. More precisely, we move by 4*7=28 days in order to preserve the original weekday.

  How to add macros to Outlook

Public Sub MoveTaskDueDates()
  Dim Exp As Outlook.Explorer
  Dim Sel As Outlook.Selection
  Dim Task As Outlook.TaskItem

  Set Exp = Application.ActiveExplorer
  Set Sel = Exp.Selection
  If Sel.Count Then
    For Each Task In Sel
      Task.DueDate = DateAdd("d", 28, Task.DueDate)
      Task.Save
    Next
  End If
End Sub