Check the current owner of the table using the below query where table_name is the name of your table and schema_name is the name of the schema in lower case.
select tableowner from pg_tables where tablename='table_name' and schemaname='schema_name';
Change the owner of the table using below command where new_owner is the name of the new owner
ALTER TABLE schemaname.tablename OWNER TO new_owner;
commit;
Verify the change by running the select command again.
select tableowner from pg_tables where tablename='table_name' and schemaname='schema_name';