I can't see find a way to UN pair the remote to the TV. When I turn off the Roku box, I don't want it also turning off the TV. Clearly I wasn't paying close enough attention.
As long as they are plugged into live power, Roku streamers (as opposed to Roku TVs) do not shut down**. The power, volume, and mute controls on the remote act on the TV, not the Roku.
So when you wish to switch the TV away from the Roku, just switch the input on the TV to what you wish to view without hitting the Roku remote power button. Since the Roku will still be running, whether you hit the Roku remote power button or not, it's a good habit to switch the Roku to Home before leaving to prevent it from streaming unwatched.
If you really want to decouple the power, volume, and mute TV controls, set it up for your TV again, but lie to it when the sound cuts off so that it goes on to try the next set of control codes. When you get to one that doesn't kill the sound, say it does.
** The Roku 4, with a built in cooling fan, is the only Roku device that could be powered down from its remote.
On your remote:
Click --> Home
Scroll and select --> Settings
Select--> Remotes & devices
Select--> Remotes
Select--> The Remote that you want to unpair. Be careful, this will list all remotes that are paired with this Roku device. Ensure that you select the correct one.
Select-->Forget remote
Confirm
That's it. HOPE THIS HELPED!
That only makes the Roku forget the remote for now, but one press of a button on the remote itself and it's back on the list and controlling the Roku.