CarPlay defaults to the first iPhone it was paired with, which can be inconvenient for anyone who regularly uses two phones in the same vehicle. The Engadget guide addresses this scenario by explaining how to get CarPlay to switch to a different iPhone.
The instructions center on overriding that automatic connection rather than accepting the original device as the permanent choice. Since the article is the only source here, there are no differing accounts or alternative methods to weigh.
The key takeaway is straightforward: CarPlay's first-paired preference is not fixed, and users who need a different phone connected can take steps to make that happen.