We can change the dfc.properties dynamically without restarting the App. server. Knowledge of JMX is required to do so.
To change the dfc.properties.
Open jConsole (Refer JDK documentation on using jConsole)
Connect to the managed JVM
From the MBeans tab, navigate to com.documentum.dfc/Preferences/Active node.
Modify the values as required
However we should declare the JVM containing the application server as JMX managed.