Inherancing

Hi people,
supposing i have the tables :

create table cities (id int, name varchar, primary key(id) );
create table centers (state varchar(2)) inherits (cities);

ant the tuple
insert into cities values (1, 'Lajeado');

How i do if i want to make this city as a center ?

Thanks,

xx===============================xx
||  °v°   Nasair Junior da Silva ||
|| /(_)\  Linux User: 246054     ||
||  ^ ^   njunior@univates.br    ||
||CPD - Desenvolvimento          ||
||Univates - Centro Universitário||
xx===============================xx