If you want to make any changes to a Workflow it can be downloaded in ZIP format from the WFP Dashboard and then uploaded to the WFP Editor (Import Zip).
To download a Workflow access the Workflow Version Details panel via the curly arrow on the Workflow Details panel. Click on the Version that you wish to download and then select the download button at the top of the panel.
Once the zip file has been downloaded locally, it can then be uploaded to the Windows Editor via the menu (top left):
Downloading a Workflow (zip)