Revert to Default Pattern Template ⌃⌥⇧D

Clear all of the Step Sequencer steps, reverting to the default template.

Customize the Step Sequencer interface in Logic Pro — Apple Support

You can clear the pattern configuration data so that new patterns, and the default view, appear as they did before the “Save as Row Default” option was used.

• In Logic Pro, with the pattern open in Step Sequencer, choose Functions > Revert to Default Pattern Template from the Step Sequencer menu bar.