Answer courtesy of C. LePard, DXC Technologies
The DUNS number can be changed by a Company Administrator In Administration… Company. In the Search Results pane, select your company, right-mouse-click (or use the “Menu” button), then select “Edit”. Do NOT double-click on the Company in the search results as you may routinely do, as the double-click action is View Company Details, which does not allow editing. The Company Details Edit window allows changing the DUNS numbers for both the Company and any Org Units. Note that Company Name cannot be edited; a Company Administrator must email the Helpdesk to request a company name change. Justification may be required.