To change the document type, you can follow these steps:

1. Open the document store.

2. Select the file that you want to amend.

3. Click on the actions icon.

4. Choose the "Edit" option.

5. In the editing mode, you will be able to make changes to the document name, owners, document type, purpose, and expiry date.

By following these steps, you can easily modify the document type and other details according to your requirements.