how can i modifie capabilities with phpmyadmin ?

Hello,

After some troubles with a plug in, so i want to restore some capabilities to admin role. But unfortunately, i can’t access to wp-admin panel.

So can you tell me :
– If i can modifie capabilities using phpmyadmin
– what are the differents tables to modified
– the process to modified (delete or add) capabilities.

Thank you for helping,