First go to the Admin Panel, then open the Users Page
Enter the username of the account for which you want to update password and hit Enter.
Now you can see that particular user account's details.
You will see these 4 icon on the right side of the page, as highpghted.
Cpck on the Lock icon to update password (Make the word Lock bold)
On this page, enter the new password twice.
After that cpck on the Update button (make the word Update bold)
Now, the user can login using the old username and new, updated password.