As system security officer, drop a role using :
drop role role_name [with override]
where role_name is the name of a user-defined role.
with override revokes all access privileges granted to the role in every database on the server.
If you do not use with the override option, you must revoke all privileges granted to the role in all databases before you can drop the role. If you do not, the command fails. To revoke privileges, use the revoke command
You need not drop memberships before dropping a role. Dropping a role automatically removes any user’s membership in that role, regardless of whether you use the with override option.
