It's common for a user to forget or misplace a password. Luckily, it is very easy to reset it.
If you are able to access Users, you can reset a password.
Go to Settings>Users
In the list view that appears, find the user and click Edit
In the pop-up window, look for the Password field. Enter a new password.
Note #1: A password must be at least 8 characters and can be any combination of letters, numbers, or special characters. It is also case sensitive.
Note #2: If there is a password visible, this means the user has not logged in at a computer and changed his temporary password. m-Post and Patrol only users (a.k.a. device only users) will never be prompted to change their temporary password.
Once done, click Update.