One thing they could do is invest in ARM manufacturers, and / or startups that are in the ARM business. As these companies grow and Intel shrinks, slowly let the investments eat themselves from the inside. For example, every few years one of Intel's fabs could be traded to one of their ARM investments. Later, as executives retire, leadership from the ARM manufacturers or startups become Intel executives. (Edit: This is what Disney did with Pixar.)

Another thing they can do is very openly admit that they are being disrupted. The CEO can basically dictate that they have to get into the ARM market and sell ARM chips according to similar terms as existing ARM manufacturers. According to "The Innovator's Dilemma," this approach is hard to do. (Edit: It's hard to do because institutional momentum and personal habits and assumptions are very hard to break.)

And, another thing is that Intel could start a business unit that behaves like a startup. It would get the majority of the CEO's attention; with running the existing business falling to other executives and managers. This new business unit would follow the ARM rules; and it would grow at the expense of the rest of the business. Intel might even need to sell their own computers.

Honestly, I suggest reading the book. It explains it better than I can. (I also suggest watching how major car manufacturers switch to Electric. GM and VW seem to be doing this.)