Prerequisites
Step 1: Copy custom theme and rename to a different name
Step 2: Register the new theme as shown below in angular.json

Step 3: Update eager-theme.module.ts
to use your new theme as shown below

Step 4: Activate the new theme in config/config.[dev/prod].yml as shown below

Step 5: Re/start the application by running yarn start:dev
for the changes to take effect.
NOTE: Changes in i18n can be updated with yarn merge-i18n -s src/themes/[theme-name]/assets/i18n