To fix the issue as suggested, change Macro2 to
Sub Macro2()
Dim vFindText As Variant
Dim vReplaceText As Variant
Dim oRng As Range
Dim i As Integer
Dim lAsk As Long

    vFindText = Array(Chr(176), Chr(177))
    vReplaceText = Array(-3920, -3919)
    For i = 0 To UBound(vFindText)
        Set oRng = ActiveDocument.Range
        With oRng.Find
            .Text = vFindText(i)
            Do While .Execute
                oRng.Select
                lAsk = MsgBox("Replace Symbol", vbYesNoCancel)
                If lAsk = 2 Then GoTo lbl_Exit
                If lAsk = 6 Then
                    oRng.InsertSymbol Font:="Symbol", _
                                      CharacterNumber:=vReplaceText(i), _
                                      Unicode:=True
                End If
                oRng.Collapse 0
            Loop
        End With
    Next i
lbl_Exit:
    Exit Sub
End Sub