It is definitely possible! It would take some coding though using the SDK Script activity in workflow. I would also suggest NOT installing MS Office or using any of their interops on the workflow server. Instead, you can use a .Net open source library that manipulates Open XML spreadsheets. Here is a good/free one. Next, you will need the Laserfiche SDK Documentation to guide you in your quest. In the documentation, there is a class called "DocumentExporter" and "DocumentImporter" in the "Laserfiche.DocumentServices" namespace. The "DocumentExporter.ExportElecDoc" will get you the document into a "Stream" from which the "SpreadsheetLight" can load it, manipulate it, and then "DocumentImporter.ImportEdoc" can then import it back to the entry, replacing the document that was there previously. I would suggest not doing to much manipulation (iterate through a large spreadsheet) as you don't want to hang up Workflow for to long. This is very high level, but it is possible.