Since the question I linked you too in my comment does not have an accepted answer (the user never choose to answer or reply to my suggestion), I will provide the solution to your problem here as well.
Sub slicers(slName As String)
Dim slItem As SlicerItem, slDummy As SlicerItem
Dim slBox As SlicerCache
Set slBox = ActiveWorkbook.SlicerCaches(slName)
'loop through each slicer item
For Each slItem In slBox.SlicerItems
'show all items to start
slBox.ShowAllItems 'or .ClearManualFilter
'test each item against itself
For Each slDummy In slBox.SlicerItems
'if the item equals the item in the first loop, then select it
'otherwise don't show it (thus showing 1 at a time between the nested loops)
If slItem.Name = slDummy.Name Then slDummy.Selected = True Else: slDummy.Selected = False
'more code to process the data (I suspect)
Next slDummy
Next slItem
End Sub