Hi @Nipun Gunaratne ,

I don’t think there will be a process to transfer the document class. Only possible way is to do a proper data repair by checking all relevant tables.

No, there is nothing out of the box for switching or reassigning a document class.  The document would need attached again with the correct class.  The only way to really address this systematically is to prevent the problem, which is actually pretty hard to do when it is users making the selection.

If this only happens now and then, you can use the Copy Document Title command, available in the Document Revision as well as the Document Titles screens. When the dialog opens, select the right document class. You now have a more or less complete copy, including all the object connections and you can now make the old document obsolete and delete it. Actually changing the document class is not possible today without writing a script to do it, as someone already said.
 

I posted this on the idea wall:

Change a document's Doc Class | IFS Community

Thanks!