After I run the command below, I can't undo. What change should I make to
make it undo-able.

Thanks.

Sub CopyFormula()

Dim myRng As Range

'single area at a time
Set myRng = Selection.Areas(1)

With Intersect(myRng.EntireRow, ActiveSheet.Range("r1").EntireColumn)
.Copy
With .Offset(0, -12)
.PasteSpecial Paste:=xlPasteValues
With .Resize(, 2) 'same number of rows, but two columns
.Replace What:="=", _
Replacement:="=", _
LookAt:=xlPart, _
SearchOrder:=xlByRows, _
MatchCase:=False, _
SearchFormat:=False, _
ReplaceFormat:=False
End With
End With
End With
Application.CutCopyMode = False
End Sub