When exporting a one-to-many field or a summary field in an export, renaming one of the column headers changes the column headers for all corresponding fields.
For example, when exporting Phone information multiple times and renaming the first column header to Home all other Phone fields are changed to Home, Home_1, Home_2, etc.
Download and install the latest patch, which contains all fixes from previous patches. If you are running an older version, download and install the latest version and then the patch.
Please review How to edit column headers in Export for step-by-step instructions on this feature. This feature works when exporting to Excel or CSV. It is not an available option if the Export is a Blackbaud Simple Mail Merge, Blackbaud Conditional Mail Merge or a Blackbaud Report Writer Database type.