Stop all outreach to a person without deleting them. Reversible at any time.
Click "Contacts" in the sidebar.
Tick the person.
Click "Actions".
Click "Do not contact".
Confirm. They are removed from every sequence, and no step, agent or Max will reach them again. The contact record stays so you keep the history.
To undo, select them again and open "Actions".
Click "Allow contact again".