Can we override (redeclare) same attribute into same Type ?

Hi Experts, I am trying to provide default values to an OOTB attribute of a existing type (Product), I redeclared same attribute with same 'qualifier' value(Like : code) by using the keyword 'redeclare="true"' But I want to define it into same type (In 'Product' Only) instead creating new customized type or sub type, is this feasible, if yes then how ? Please suggest.

Thanks, Prahlad