Which version of Ambari you are using? Ambari doesn’t support to transfer service explicitly. But you can always remove a component from a host and add it back to another host.
FYI, in Ambari 1.4.x, it supports to add some non-master components/services after the installation.
For example, you can add zookeeper server, HDFS Client and etc.
But for the Namenode, Resource Manager and other master service, I don’t think you can add these master component to the cluster after the installation.
Hopes this help.