This is the shipped VLF-ONE Change Password ancestor which handles requests to change a user's password.
The default reusable part is named VF_AC027O. It is shipped with source code. Read the comments in the source code to learn how to use it.
You must not use VF_AC027O in production systems. Instead replace it with your own Change Password reusable part that has ancestor VF_AC027O.
This property is in the Framework User Administration Settings tab.