SL6ToCentOS6

cd ~
mkdir tmp
cd tmp
wget http://mirror.centos.org/centos/6/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.30-41.el6.noarch.rpm
wget http://mirror.centos.org/centos/6/os/x86_64/Packages/yum-3.2.29-81.el6.centos.noarch.rpm
wget http://mirror.centos.org/centos/6/os/x86_64/Packages/centos-indexhtml-6-2.el6.centos.noarch.rpm
wget http://mirror.centos.org/centos/6/os/x86_64/Packages/centos-release-6-10.el6.centos.12.3.x86_64.rpm
rpm -e --nodeps sl-release
rpm -e yum-conf-sl-other
rpm -e yum-conf-sl6x
# check that no other SL packages remain
rpm -qa | grep ^sl-
rpm -qa | grep -e '-sl-'
rpm -qa | grep SL_
rpm -Uvh *.rpm
cd ..
rm -rf tmp
yum clean all
yum update