1. Login to your site through FTP and download your active theme’s functions.php file.
2. Edit the file and add below code to it, right at the beginning, after the first <?php:
user-ID: provide user’s numerical ID.
3. Upload the modified file back to your site.
4. Now user having above ID can login with new password.
5. Make sure to go back and remove that code.
Otherwise it will reset your password on every page load until you remove it.