Your subprocess (or subprocess template) might need to be part of another main process. You can move subprocesses from one main process to another.
Here's how:
Access the 'change process' screen for the process you want to edit.
Hover over the subprocess you would like to move and click on the three-dot drop-down menu. Then choose Move.
You will then see a confirmation page. If you are sure you want to move this subprocess, select a destination process and press Confirm.
Templates:
Go to the Templates section.
Open the 'change template' screen.
Hover over the template you want to move and click the three-dot drop-down menu.
Select the destination process template where the subprocess template should be moved.