yes, it will automatically rebuild it ..always do an upgrade, you don't need to uninstall it first.

Take a look at this guide, page 73

https://support.emc.com/docu42959_PowerPath-for-Linux-5.7-and-Minor-Releases-Installation-and-Administration-Guide.pdf

Thanks but what I'm asking is what happens to powerpath if I install a patch that upgraades the Linux kernel. I'm assuming that the Powerpath kernel modules will need to rebuild against the new kernel. How does that happen?

In family updates and patches should be all right, but you have to always compatibility matrix.

as long as the kernel is supported, PowerPath module will be loaded just fine. I have not had to mess with PowerPath after installing kernel upgrades.