We are having an issue with CDT reference. We got to change the namespace of CDT

Does the process Models could refer to this new CDT after updating the namespace ?

AFAIK a CDT is referenced by namespace and name. So when you change the namespace Appian is not able to update references and impact analysis will not find anything. You will have to update all references by hand.

Just to complement what has been already said:

Impact Analysis inspects every single item in your applications under the Applications tab to determine what objects make reference to the selected CDT. Once CDTs are registered/created in Appian Impact Analysis will identify them as unique through their name + namespace combination; that said when you change the namespace this CDT is no longer a version of the deleted one, it's a completely new one since the identifier name + namespace is no longer the same, that makes Impact Analysis unable to think that object A referencing {old_namespace}myCDT is now supposed to make reference to {new_namespace}myCDT.

This behavior is expected since Appian cannot guess that {old_namespace}myCDT is supposed to be now a new version of {new_namespace}myCDT; there's nothing that could link those CDTs specially since the way you created the new one was by deleting the old and uploading the new one; notice how at no point there's an association when you upload a CDT with a deleted one other than the one that gets created if you keep the original name and namespace.

In summary, when updating a namespace you need to:

1. Upload the CDT with the new namespace
2. Manually update your models/objects to point to the new CDT
3. Only at this point you can delete the CDT with the old namespace.

Thanks for the reply. We updated all the reference manually.

@Eduardo, We have designed all our process models with proper readable flow including swimlanes. Now all of a sudden swimlanes are lost and process models are saved with improper connections.We even restarted the server and no change to the flow.
Is this namespace change impacted process models?

This means the CDTs were deleted before all nodes were remapped now when you try to open the model retrieving it from the file system fails because of the deleted and renamed type.

To fix this:

1. DO NOT PUBLISH the broken look and feel, if you already did you basically saved that "broken" look and feel.
2. Re-upload the CDTs with the old namespace
3. Open the model to confirm that if you never saved the wrong look and feel then your original position, lanes and annotations will be there.
4. Remap any missing nodes and variables that could be pointing to the old namespace
5. Publish your model
6. Only at this point is safe to remove the old CDTs