Sub Cmts()
Dim cmt As Comment, ws As Worksheet, s As String
s = InputBox("Enter old username")
For Each ws In ThisWorkbook.Worksheets
For Each cmt In ws.Comments
With cmt.Parent
.NoteText Text:=Replace(.NoteText, s, Application.UserName)
End With
Next cmt
Next ws
End Sub
Sub Cmts()
Dim cmt As Comment, ws As Worksheet, s As String
s = "Edward"
For Each ws In ThisWorkbook.Worksheets
For Each cmt In ws.Comments
With cmt.Parent
.NoteText Text:=Replace(.NoteText, s, Application.UserName)
End With
Next cmt
Next ws
End Sub