You can manage subsystems by using a JMX client under MBeans > Alfresco > Configuration > ContentStore > managed. Here, you can change all the properties defined for the subsystem, and restart the subsystem. Another way to extend a subsystem is to add a *-context.xml and a properties file, in the extension path for that subsystem:
alfresco/extension/subsystems/ContentStore/Azure/Azure/*-context.xml
alfresco/extension/subsystems/ContentStore/Azure/Azure/*.properties
Note
In Content Services 7.2 and Azure Connector 3.0, changing the current content store subsystem using the JMX client isn't supported. There's a limitation in Content Services which only allows switching between the embedded content stores.