You need to erase it from the ECU, depending o the other car you paired it with, some you can do by re-programming the key you want for that car and just don’t use the key you want to use only on the one car, on some cars that will remove any currently programmed remotes and only recognise the one you’ve just done, on some others you may need a car key technician to come and delete it via a computer, what is the other car you paired it with, is it the same Toyota?