Arduino interrupts


I know that codecademy doesn’t offer courses on arduinos but this forum is as good a place as any to ask questions, right? So I was looking into external interrupts and I understand that you can use detachInterrupt() to disable an interrupt but what if I want to re-enable the interrupt in certain circumstances? attachInterrupt() has to be declared in void setup() so I don’t think I can reuse it in void loop(), google searches on this topics have been tasteless for me.