Change user password in database

Hi,
We use Keycloak with AWS RDS (PostgreSQL), is it possible to change a users’ password in the database?

The reason i’m asking; somehow we lost access to our master realm admin user. We do have another realm with an admin user in it that we do have acces to but when i use that one with kcadm.sh, it throws “null [unknown_error]” errors when attempting to do anything with the master realm.

Help is appreciated! Thanks!