My conclusion is it can't be deactivated once awakened. It's quite a price to pay for awakening such great power cause let's admit it, there's no eye so revered and so potent as the aforementioned in narutoverse. All the strongest villains had it. If you don't believe me.
Let's recap a tad-bit:
1. Madara Uchiha
2. Kaguya Otsutsuki
3. Obito Uchiha
4. Nagato Uzumaki
5. Sasuke Uchiha
6. The aliens (Momoshiki)
Toneri is about the only "real" villain in the anime who didn't have it.
My point is: the Rinnegan just like the Mangekyou Sharingan has its "ugly" side. Which is one can't simply deactivate it and since it's as if you got a new eye it only makes sense you can't reverse the process
Let's recap a tad-bit:
1. Madara Uchiha
2. Kaguya Otsutsuki
3. Obito Uchiha
4. Nagato Uzumaki
5. Sasuke Uchiha
6. The aliens (Momoshiki)
Toneri is about the only "real" villain in the anime who didn't have it.
My point is: the Rinnegan just like the Mangekyou Sharingan has its "ugly" side. Which is one can't simply deactivate it and since it's as if you got a new eye it only makes sense you can't reverse the process