They are 2 fundamentaly different line of actions by a company.
In a stable envronment where the market boundary has been clearly defined, companies can apply the porter model to analyze where they are and how they can shift towards a more favourable position.
For example the airline industry opting for mergers and acquisitions for the rationalization of routes is a concrete step which is the outcome of the porter analysis aimed at reducing ustomer bargaining power.
However companies can also disturb the status quo by changing the rules of the market. In other words the market institutions can be manipulated to attain super normal profits. This scenario is not an application of porter.
For example the setting up of priceline.com allows the airlines to o price discrimination without affecting their existing business. Priceline has lead to the creation of a whole new market which is not the outcome of a porter analysis.