You can delete individual automation points, multiple automation points, or use a number of commands to delete automation across tracks.
The commands to delete automation are only available when Show Advanced Tools is selected in the Advanced preferences pane.
Delete a single automation point
Do one of the following:
Double-click the automation point.
Select the automation point, then press Delete.
Drag across the automation point with the Eraser tool.
Delete multiple automation points
Select multiple automation points, then press Delete.
Important: Make sure that no regions are selected, or they will also be deleted.
Delete automation using commands
Choose one of the following options from Mix > Delete Automation:
Delete Visible Automation on Selected Track: Removes automation for the active automation parameter.
Delete All Automation on Selected Track: Removes all automation from the selected track.
Delete Orphaned Automation on Selected Track: Removes all orphaned automation from the selected track. Automation can become orphaned when copied between tracks.
Delete All Automation: Removes all automation from all tracks.