Realignment

Hi,

i am working with realignment concept.

here, i had almost 500 materials that i need to do realignment as the material numbers being chagned in my plant,

my question is, if there are few materials we can simply do manually, for a large number of materials is there any way to do other than manually entering each material??

i need to chagne two char only i.e.material and subgroup,

your suggestion are highly appreciable

thanks

Arun R Y