XML DB :: Possible To Remove XMLSchema Restriction From XMLType Column?

I have an XMLType column that is validated via some XMLSchema. Now I want to remove this restriction and make it just a generic XMLType column. I tried bunch of alter table commands but I couldn't figure out the magic combination. Is this possible?

Here is the actual problem. Unfortunately, we ended up both local and global schemas using the same URL. We have customers out there with both schemas (early customers) or only global schema (new customers). Most of the tables were created before the global schema was added. So, they are referencing the local schema. Now we want to evolve our schema, and I am trying to write a sql script to clean-up this mess. if only global schema exists then (these are late customers)

- do nothingelse if both global and local schema exist then (these are early customers)
- If any table or table.column has dependency on local schema (I can find this out from user_dependencies) I am going to mark those tables/columns as no schema validated. i.e. remove all references to local schema
- delete and purge the local schema
- modify those tables/columns and make them point to the global schema end if
- evolve the schema (only global one is left)

Is there a way to modify a column definition and move its reference from local schema to global schema where both schemas have the same URL? Of course the main constraint is that we do not want to loose customer data. By the way, both local and global schemas are identical in terms of xsd.

is it possible to change XMLSchema/Element settings of an XMLType column from X to Y, X to null, or null to X?