This question seems to be quite popular so I would link to one of the previous discussions. In short you have these options
- load the existing data, manipulate it in KNIME so you have new lines with the ‘report’, export the data again. That would work but maybe destroy your formats. You could help yourself with the Continental Excel nodes that allow the formatting of existing Excel files.
- next strategy could be to separate your data sheets and reports. Have a very nice reporting sheet that you fill with References, Matrix commands and the like in Excel from a plain data sheet. That data sheet can easily be populated using the Excel Sheet Appender.
- and then there is the way to use Python (require some programming efforts on your side)