When exporting Revit data to an existing Excel file, there are two possible options using Ideate BIMLink
An existing Excel file contains one or more worksheets, but none of the existing worksheets have the same name as the link being exported.
In this case, a new worksheet with the link name is inserted in the existing Excel file.
An existing Excel file contains one or more worksheets, and one of the existing worksheets has the same name as the link being exported.
In this case, the existing worksheet is overwritten with the most recent link data. For example, if you export the same link multiple times to the same Excel file, the file will only contain the most recent link data exported.