Do you mean you want to install the Share web-app on a different machine to the one running the Repository (alfresco.war)?
Assuming so, the process is much the same as for changing the port - you need a
share-config-custom.xml
which points to where the repo lives. See the <a href="http://docs.alfresco.com/4.2/tasks/share-change-port.html">Configuring the Share default port docs</a> for more. Also, don't forget to setup your firewalling to allow the Share webapp to talk through to the Repo!
