Bulk update of supplier site zip codes

Summary:

We need to update the zip codes of most of our suppliers so that it displays the zip code plus 4 values. We have thousands of vendors in our system that would require this update, some with multiple supplier site addresses that have different zip codes. Is there a way on the back end to upload a spreadsheet to update the values or do a bulk update for multiple addresses at once so we can make the adjustments we need without having to go into the interface and update each individual zip code?

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