This applies specifically to AsgardCMS which is a Laravel based CMS and can be easily tweaked to work with any Laravel application.

First you need to open tinker from your app root folder:

php artisan tinker

Query your user entity to retrieve the user we want to change password:

$user = Modules\User\Entities\Sentinel\User::where('email', '')->fisrt();
$user->password = Hash::make('new_password');