«User's Passwords» plugin is a tool of site's managers and administrators, which allows to install and send a new password to any site's user. In addition, you can log in to the site on behalf of the user without requesting or changing his password.
The plugin will help you in cases when:
a user has lost access to the account or forgotten the password;
a user can't recover the password by himself;
you need to look at the site through the user's eyes.