Version EP 7.3 , User should have System Administrator permission.
Edit UME Online
Administrators can edit online in EP7.3 by navigating from Expert mode of the user management configuration tool which enables you to change user management engine (UME) properties online at the global level. Use expert mode to configure UME properties for which there is no other user interface.
Navigated to System Administration -> System Configuration -> UME Configuration.Choose Open Expert Mode as shown below.
Search for the UME Property and choose Modify to change values.
Choose Save after modifying the value.
Restart AS Java if required.
Note : Editing UME Properties using Config tool available as like earlier versions.