After merging a document with data placeholders on master pages, you can change the layout of the merged document and still update the values of data fields in the data source. Use the Update Data Fields to update the data fields while maintaining the layout of the document. This option is available only in a merged document in which data placeholders appear on master pages.

The changes that have been made by updating the data fields appear in a log file.

This option works best when you simply edit or add records in the data source file. If you add placeholder fields, add new fields to the data source, or change the settings in the Create Merged Document dialog box, use the Create Merged Document option to generate a new merged document.