Once your automation is published, you cannot edit it.
Get started
Navigate to Email Center → Email Automation from the top menu
You can edit your automation from the listing screen or on the individual automation page.
Editing an automation from the listing screen
Click the "pencil" icon in the list of available actions for your automation
Editing an automation from the individual automation screen
Click the name of the automation from the listing screen
Click the "pencil" icon in the top right corner.
Make any changes
"Save Automation"