juju-local was already in main, but juju-core is seeded and was not.
$ ./change-override -c main juju-core
Override component to main
juju-core 1.24.6-0ubuntu2 in wily amd64: universe/devel/extra/100% -> main
juju-core 1.24.6-0ubuntu2 in wily arm64: universe/devel/extra/100% -> main
juju-core 1.24.6-0ubuntu2 in wily armhf: universe/devel/extra/100% -> main
juju-core 1.24.6-0ubuntu2 in wily i386: universe/devel/extra/100% -> main
juju-core 1.24.6-0ubuntu2 in wily powerpc: universe/devel/extra/100% -> main
juju-core 1.24.6-0ubuntu2 in wily ppc64el: universe/devel/extra/100% -> main
Override [y|N]? y
6 publications overridden.
juju-local was already in main, but juju-core is seeded and was not.
$ ./change-override -c main juju-core devel/extra/ 100% -> main devel/extra/ 100% -> main devel/extra/ 100% -> main devel/extra/ 100% -> main devel/extra/ 100% -> main devel/extra/ 100% -> main
Override component to main
juju-core 1.24.6-0ubuntu2 in wily amd64: universe/
juju-core 1.24.6-0ubuntu2 in wily arm64: universe/
juju-core 1.24.6-0ubuntu2 in wily armhf: universe/
juju-core 1.24.6-0ubuntu2 in wily i386: universe/
juju-core 1.24.6-0ubuntu2 in wily powerpc: universe/
juju-core 1.24.6-0ubuntu2 in wily ppc64el: universe/
Override [y|N]? y
6 publications overridden.