Dim AccountManagers As Variant
xVal = Sheets("Details").Cells(Rows.Count, 1).End(xlUp).Row
ReDim AccountManagers(xVal)
AccountManagers = Worksheets("Details").Range("D2:D" & xVal)
Sheets("Summary").Range("S1").Value = UBound(AccountManagers)
Dim coll As New Collection
On Error Resume Next
For i = LBound(AccountManagers) To UBound(AccountManagers)
coll.Add AccountManagers(i), AccountManagers(i)
Next i
On Error GoTo 0
Sheets("Summary").Cells(1, 21) = LBound(AccountManagers)
Sheets("Summary").Cells(1, 22) = UBound(AccountManagers)
Sheets("Summary").Cells(1, 23) = coll.Count
'you now have a collection of the unique items from your array:
For i = 1 To coll.Count
Sheets("Summary").Cells(i, 20) = coll(i)
Next i
Dim AccountManagers As Variant
xVal = Sheets("Details").Cells(Rows.Count, 1).End(xlUp).Row
''' ReDim AccountManagers(xVal) ====== Unnecessary
AccountManagers = Worksheets("Details").Range("D2:D" & xVal)
Sheets("Summary").Range("S1").Value = UBound(AccountManagers)
Dim coll As New Collection
On Error Resume Next
For i = LBound(AccountManagers,1) To UBound(AccountManagers,1)
coll.Add AccountManagers(i,1), AccountManagers(i,1)
Next i
On Error GoTo 0
Sheets("Summary").Cells(1, 21) = LBound(AccountManagers)
Sheets("Summary").Cells(1, 22) = UBound(AccountManagers)
Sheets("Summary").Cells(1, 23) = coll.Count
'you now have a collection of the unique items from your array:
For i = 1 To coll.Count
Sheets("Summary").Cells(i, 20) = coll(i)
Next i