Best way to migrate an extension from Dahdi to SIP


We have a site that is using mostly analog phones (dahdi extensions), but we are planning on migrating them to SIP phones. Is there a way to migrate the underlying extension type from Dahdi to SIP without deleting and re-creating the extension?

Bulk export then import. Update using find/replace in spreadsheet type software.

Thank you, that will save me a lot of time and aggravation!