I have never done it, but I do have a Wii with Netflix & this is how I would go about doing it. Again, I don’t know if this will work, but it is all I can think of.
Use computer to go to Netflix. Click on ‘Your Account & Help’ in the top right of the page.
Click on ‘Manage Netflix ready devices and computer’.
In the list of devices, find the Wii & click on the ‘Deactivate’ link.
Now, when at the main screen on the Wii, go into the system settings & the save data information. Delete all the Netflix related save files.
At this point I believe you can activate Netflix on the Wii as you would if it was for the first time.
Hopefully this works. I can’t imagine why it wouldn’t.
EDIT.. Since you already figured it out, could you explain how you did it (if different from my explanation) here in the forum – for future reference? Thanks.