E1 41 How to change cost method from 02 average to 07 standar for components

Hi everyone, hope someone can help me.

I have a question,  our customer is on JDE 9.2 working with mixed manufacturing, I mean finished goods and subassemblies have standar cost 07 and components or raw materials have cost method 02 average, now they want to change cost methow for raw materials to 07 standar.

They have open work orders for finished items and sub assemblies, for raw materials they have inventory on hand.

In this scenario ¿what is the best way to change cost method 02 to 07 for raw marerials and the impact? 

Regards