Once you know how to create a Macro and move around in Macro design view, editing a Macro is actually rather easy.
However, when editing a Macro you’ll want to remember to open your Macros in Design View because double-clicking a Macro to open it will run it. And, since Macros are like Action Queries in that they can make permanent changes to your database data, it’s a good habit to open them in Design View.
Right-click the macro you want to edit in the Database Window
Choose Design view
Make your changes
Save the Macro