Running Process Runs can be cancelled from the Process Runs screen. Clicking on the cancel icon in the actions toolbox.

It can also be done from the Cancel Process Run button on individual Process Run screens

Upon clicking the Cancel icon or button, a confirmation prompt will appear.

After cancellation, any incomplete tasks will be cancelled, and no new tasks will be created, and completed work will remain unchanged.
The run status will be updated to Cancelled, incomplete steps will be marked as cancelled.
Stage status will remain in whatever state it was at cancellation.