You can easily change or reset a password
Find the trainee by searching for them.
Click on Edit
Or if you see the Trainee options menu on any page, then choose Edit from there
You can now change the groups the trainee belongs to, their name and their password.
Type the new password and click Save. Editing a password doesn't update the trainee - you'll need to notify them. A trainee can also edit their own password by logging in and clicking on Profile.