Outside operations (X stocking Type)

Hello JDE Community

I've a question regarding Outside Operations

We have a request from business where they no longer want to use the Outside Operation for one of the manufacturing line.

If we have changed our routing so we no longer use a *op process can we change the stocking type to say O obsolete without breaking the link to the original item or is there a different way of doing this? 

If we have changed an item to obsolete is it going to cause any problem on the SO side ?

In short:

(a). What changes are required at the routing side.