Not sure what you mean when you say your data source is a workbook. However, to change data sources you can connect to the new one, right click the old one and click "Replace Data Source".
Please note that this can sometimes cause you to lose some formatting, specifically colors / quick filters. I would recommend opening each tab in the workbook at least once before doing "Replace Data Source". This seems to minimize the amount of formatting stuff lost.
It is highly recommended to first save your workbook with different name so that it can be updated with another version for data source. Next, find the updated data source to replace and be careful to compare that the names and data types are exactly same. Accuracy checks for metadata are essential.As the data loads, be patient and review the calculated fields for any red exclamation marks or other alerts.