Sub TransposeRowsInGroupsOf13()
Dim X As Long, LastRow As Long
LastRow = Cells(Rows.Count, "A").End(xlUp).Row
For X = 1 To LastRow Step 13
Cells(X, "A").Resize(, 13).Value = WorksheetFunction.Transpose(Cells(X, "A").Resize(13))
Next
Columns("B").SpecialCells(xlBlanks).EntireRow.Delete
End Sub