Senario:
Our webservers use a database backend which is also replicated to two other servers. In the even that there is a failure then one of the others can take over. oldserver1.berlinschools.org was not doing well and was also the master in a mysql replication setup with two "slave" servers. One older (olderserver2.berlinschools.org) and one basically new (newserver.berlinschools.org). The need was to make it so oldserver1's master status was passed onto newserver and oldserver2 would look to ne for slave updates.