Note: The following description applies both to Postgres-XC and PostgreSQL if not described explicitly.
ALTER SCHEMA changes the definition of a schema.
You must own the schema to use ALTER SCHEMA. To rename a schema you must also have the CREATE privilege for the database. To alter the owner, you must also be a direct or indirect member of the new owning role, and you must have the CREATE privilege for the database. (Note that superusers have all these privileges automatically.)