Thank you for the response. What i was looking for is to change the user Admin password, not the osgi Admin user password. I finally figure it out how to do this with a workaround.
1. naviate to the publish instance crxde. http://localhost:4503/crx/de
2. Login using Admin userID and password
3. In the same session change the URL to http:/localhost:4503/projects
4. Now you can navigate to tools > Operations > Security > users to change the admin user password
Note: What I wanted to do is to remove or disable the Admin and any other build in user for security reasons, but this is not allowed. Not sure if this can be done in AEM 6.1. Will need to try that later.
