@billknguyen it might be best to open a new thread for this question. But there has been a thread about excel and keeping formats here. Maybe you check the suggestions there.
@helpmeplease if you want the structure of your Excel file unchanged and just change values there are these options, if you must change data on a pre-formatted sheet (otherwise you might just replace this sheet). The Excel Cell Updater can change values in specific cells.
You can use a community node to write to an Excel file without changing the structure or formats:
You can the use Python and OpenPyxl to do more complex editings of excel files. You will have to plan ahead what this d…
With the Excel Cell Updater – KNIME Community Hub there is a dedicated node for that.