Once you have modified the external JRE, you can configure the server to use the external JRE by performing an upgrade installation of the server. During the upgrade, you will be prompted specify whether you are using the embedded JRE or an external JRE. If you select external JRE, you must specify the path to the external JRE.
If you are using a response file to perform a silent upgrade, best practices recommend that you use the installation program to generate the response file. However, you may opt to edit the response file manually. If editing the response file manually, you must add Java configuration options to the response file. The options and values depend on whether the response file is based on the GUI installation template or the console mode installation template.