[kolla] How to patch images during build

Folks,

I'm using kolla-build to build all images and push them to the local repo. So far all good but let's say If in future for some reason I want to patch some bug and rebuild the image in that case how do i patch kolla images?

I am reading at [1] and didn't see any example to patch Image for any bug.

Should I be downloading tarball and patch it and then use type=local to build the image from local source or add patch to Dockerfile? What people use for best practice for this kind of thing?

[1] https://docs.openstack.org/kolla/latest/admin/image-building.html