set-dates

Function IsDate(cellValue) As Boolean
    If Len(cellValue) > 9 Then
        IsDate = True
    Else
        IsDate = False
    End If
End Function

Sub SetDates()

    Dim SelectedRange As Range
    Set SelectedRange = Selection
    
    RowCount = SelectedRange.Rows.Count
    
    FirstRowIndex = CInt(Split(SelectedRange.Cells(1).Address, "$")(2))
    LastRowIndex = FirstRowIndex + (RowCount - 1)
    
    Dim GroupDate As String
    For i = FirstRowIndex To LastRowIndex Step 1
        
        Dim CellValueColumnA As String
        Dim CellValueColumnB As String
        
        CellValueColumnA = Cells(i, "A").Text
        CellValueColumnB = Cells(i, "B").Text
        
        If IsDate(CellValueColumnA) And CellValueColumnA = CellValueColumnB Then
            GroupDate = Cells(i, "A").Text
            MsgBox GroupDate
        Else
            MsgBox GroupDate
            Cells(i, "A").NumberFormat = "@"
            Cells(i, "A").Value = GroupDate
        End If
        
        
    Next i
    
End Sub