Hi roundamerica,
The easiest way to do this is as follows:
1) Export your existing listings under Directory Admin->CSV Export. Be sure to check the “Include unique IDs for each listing (sequence_id column).” option.
That provides you a unique ID to use for import to update, rather than insert. The column for sequence_id is automatically generated for you. If you need to use an external data source for the first time, you can skip this step and just do the import for the first round of data. This is for the second and subsequent rounds ONLY.
2) Make the necessary updates in the CSV. Whatever changes you make here are the changes that will show up.
3) Re-import the file under Directory Admin->CSV Import.
Import docs are here: http://businessdirectoryplugin.com/docs/#admin-import
Export doesn’t have docs, but the options are pretty self-explanatory. Ask questions if you disagree. 🙂
