You can edit a Magic ETL DataFlow simply by opening it in the Data Center and making the desired changes.
To edit a Magic ETL DataFlow,
Click Data in the toolbar at the top of the screen.
Click in the left-hand navigation pane.
Locate and click the Magic ETL DataFlow you want to edit.
Make any changes you want, then click Save, enter a version description if desired, then click Save to confirm.
When you save a DataFlow, an entry for this version is added to the Versions tab in the Details view for the DataFlow. If you entered a description when saving, that description is shown in the entry for the DataFlow. For more information about versions, see Viewing the Version History for a DataFlow.