Sub Macro1()
Dim ws As Worksheet
Dim lastRow As Long
Dim I As Long
Dim Rep As Integer
Set ws = Sheets("Page1_1")
Rep = MsgBox("Are you willing to copy all dates into this column?", vbYesNo + vbQuestion, "mDF XLpages.com")
If Rep = vbYes Then
ws.Select
lastRow = Cells(rows.count, 35).End(xlUp).Row
For I = lastRow To 2 Step -1
If Cells(I, 35).Value = "" Then
Cells(I, 35).Value = Cells(I, 29).FormulaR1C1 = _
"=TEXT(1*TEXT(Tableau1[[#This Row],[DocumentDate]],""0000\/00\/00""),""mm-aaaa"")"
Else
End If
Next I
End If
End Sub