Maybe I misunderstood your question. To change the
formatting (such as font and size) of the text, changing the defaults is the only way I know.
You can change the initials via a macro:
Code:
Sub ChangeCommentInitials()
Dim c As Comment
For Each c In ActiveDocument.Comments
c.Initial = "M" 'or whichever letter you want
Next c
End Sub
You can't change the actual
comment numbers, though, if that's what you are asking.