You can look at NotebookDynamicExpression.
But I echo the comment by Eric, it would be an exceedingly, and perhaps, fatal mistake to make those changes to the If statement. To misquote, Shakespeare: there are more things in heaven and If than are dreamt of in your philosophy…
There are huge amounts of Mathematica code behind the scenes, running things. And if you change that attribute, it’s likely that your entire universe will collapse around you. Be careful out there it’s wild.
