Below is an example of a For/Next loop with an 'If' statement.

I've not tested it, something you will have to do with your own VBA extensively because there are always errors Happy

But that's just one way, and there will be other methods.

The example shown below won't have the VBA indent formatting displayed in this post, because the forums don't allow more than one space between characters.

With ActiveWindow
For x = 12 To 651
Cells(x, 3).Select
If Cells(x, 3) = "Fred" Then
Cells(x, 3) = "Barney"
End With

Does that give you an idea?